diff --git a/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionComponents.swift b/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionComponents.swift
index 4e804b8..2ea3bf8 100644
--- a/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionComponents.swift
+++ b/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionComponents.swift
@@ -3,8 +3,24 @@ import SwiftUI
 struct WorkoutSessionRecordRetryBanner: View {
     let message: String
     let isLoading: Bool
+    let retryAccessibilityLabel: String
+    let retryAccessibilityIdentifier: String
     let onRetry: () -> Void
 
+    init(
+        message: String,
+        isLoading: Bool,
+        retryAccessibilityLabel: String = "이전 운동 기록 다시 시도",
+        retryAccessibilityIdentifier: String = "workout.previous-record.retry",
+        onRetry: @escaping () -> Void
+    ) {
+        self.message = message
+        self.isLoading = isLoading
+        self.retryAccessibilityLabel = retryAccessibilityLabel
+        self.retryAccessibilityIdentifier = retryAccessibilityIdentifier
+        self.onRetry = onRetry
+    }
+
     var body: some View {
         HStack(spacing: GymupSpacing.small) {
             Image(systemName: "exclamationmark.circle")
@@ -34,8 +50,8 @@ struct WorkoutSessionRecordRetryBanner: View {
             }
             .buttonStyle(.plain)
             .disabled(isLoading)
-            .accessibilityLabel("이전 운동 기록 다시 시도")
-            .accessibilityIdentifier("workout.previous-record.retry")
+            .accessibilityLabel(retryAccessibilityLabel)
+            .accessibilityIdentifier(retryAccessibilityIdentifier)
         }
         .padding(.horizontal, GymupSpacing.medium)
         .padding(.vertical, GymupSpacing.xSmall)
diff --git a/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionRestTimerScreen.swift b/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionRestTimerScreen.swift
index 2fbed53..176aecd 100644
--- a/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionRestTimerScreen.swift
+++ b/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionRestTimerScreen.swift
@@ -11,6 +11,10 @@ struct WorkoutSessionRestTimerScreen: View {
     let previousRecordError: String?
     let isLoadingPreviousRecord: Bool
     let onRetryPreviousRecord: () -> Void
+    let nextSetPreview: NextWorkoutSetResponse?
+    let nextSetPreviewError: String?
+    let isLoadingNextSetPreview: Bool
+    let onRetryNextSetPreview: () -> Void
     @State private var isPlateCalculatorPresented = false
 
     private var nextSet: WorkoutSessionSet { exercise.sets[nextSetIndex] }
@@ -38,6 +42,16 @@ struct WorkoutSessionRestTimerScreen: View {
                         )
                         .padding(.top, 12)
                     }
+                    if let nextSetPreviewError {
+                        WorkoutSessionRecordRetryBanner(
+                            message: nextSetPreviewError,
+                            isLoading: isLoadingNextSetPreview,
+                            retryAccessibilityLabel: "다음 세트 정보 다시 시도",
+                            retryAccessibilityIdentifier: "workout.next-set.retry",
+                            onRetry: onRetryNextSetPreview
+                        )
+                        .padding(.top, 12)
+                    }
                     Spacer(minLength: 64)
                     plateCalculatorHint
                 }
@@ -163,17 +177,17 @@ struct WorkoutSessionRestTimerScreen: View {
                     .clipShape(RoundedRectangle(cornerRadius: 10))
 
                 VStack(alignment: .leading, spacing: 0) {
-                    Text("NEXT · SET \(nextSetIndex + 1) / \(exercise.sets.count)")
+                    Text("NEXT · SET \(nextSetPreview?.setIndex ?? nextSetIndex + 1) / \(exercise.sets.count)")
                         .font(GymupTypography.label)
                         .tracking(0.16)
                         .foregroundStyle(GymupColors.secondaryText)
-                    Text("\(nextSet.weightKilograms.formatted(.number.precision(.fractionLength(0...1)))) KG × "
-                         + "\(nextSet.repetitions)\(exercise.measure == .seconds ? "초" : "")")
+                    Text("\((nextSetPreview?.weight ?? nextSet.weightKilograms).formatted(.number.precision(.fractionLength(0...1)))) KG × "
+                         + "\(nextSetPreview?.reps ?? nextSet.repetitions)\(exercise.measure == .seconds ? "초" : "")")
                         .font(GymupTypography.display)
                         .foregroundStyle(GymupColors.primaryText)
                         .lineLimit(1)
                         .minimumScaleFactor(0.75)
-                    Text("\(exercise.name) · 이전 \(exercise.previousPerformance(for: nextSetIndex) ?? "—")")
+                    Text("\(nextSetPreview?.exerciseName ?? exercise.name) · 이전 \(exercise.previousPerformance(for: nextSetIndex) ?? "—")")
                         .font(GymupTypography.uiCaption)
                         .foregroundStyle(GymupColors.secondaryText)
                         .lineLimit(1)
diff --git a/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionView+Actions.swift b/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionView+Actions.swift
index 50950c0..fdb798c 100644
--- a/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionView+Actions.swift
+++ b/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionView+Actions.swift
@@ -60,6 +60,7 @@ extension WorkoutSessionView {
             UIImpactFeedbackGenerator(style: .light).impactOccurred()
         }
         syncRestActivity()
+        refreshNextSetPreviewIfServerResting()
         if viewModel.currentExerciseIndex == viewModel.plan.exercises.count - 1,
            viewModel.currentExercise?.isComplete == true {
             showWorkoutProcessing()
@@ -78,6 +79,7 @@ extension WorkoutSessionView {
                 completeSetSideEffects()
             } else if let failedAction, case .startRest = failedAction {
                 syncRestActivity()
+                refreshNextSetPreviewIfServerResting()
             } else if let failedAction, case .skipRest = failedAction {
                 settings.cancelRestNotification(sessionID: liveActivitySessionID)
                 await WorkoutRestActivityController.shared.end(sessionID: liveActivitySessionID)
@@ -85,6 +87,7 @@ extension WorkoutSessionView {
                 syncRestActivity()
             } else if let failedAction, case .refreshRest = failedAction {
                 syncRestActivity()
+                refreshNextSetPreviewIfServerResting()
             }
         }
     }
@@ -114,6 +117,11 @@ extension WorkoutSessionView {
         }
     }
 
+    private func refreshNextSetPreviewIfServerResting() {
+        guard viewModel.isServerManagedRest else { return }
+        Task { await viewModel.loadNextSetPreview() }
+    }
+
     func refreshRestOnForeground() {
         guard viewModel.isServerManagedRest else { return }
         if viewModel.refreshClock(at: Date()) {
@@ -128,6 +136,7 @@ extension WorkoutSessionView {
                 return
             }
             syncRestActivity()
+            await viewModel.loadNextSetPreview()
         }
     }
 
@@ -237,6 +246,14 @@ extension WorkoutSessionView {
         DebugOnboardingNetworking.makeWorkoutSessionService()
 #else
         nil
+#endif
+    }
+
+    static func makeWorkoutReadService() -> WorkoutNextSetReading? {
+#if DEBUG
+        DebugOnboardingNetworking.makeWorkoutReadService()
+#else
+        nil
 #endif
     }
 }
diff --git a/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionView+Content.swift b/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionView+Content.swift
index 604550c..ed5ebca 100644
--- a/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionView+Content.swift
+++ b/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionView+Content.swift
@@ -36,7 +36,11 @@ extension WorkoutSessionView {
                     onSkip: skipCurrentRest,
                     previousRecordError: viewModel.previousRecordError(for: exercise.id),
                     isLoadingPreviousRecord: viewModel.isLoadingPreviousRecord(for: exercise.id),
-                    onRetryPreviousRecord: { Task { await loadPreviousRecord(for: exercise.id) } }
+                    onRetryPreviousRecord: { Task { await loadPreviousRecord(for: exercise.id) } },
+                    nextSetPreview: viewModel.nextSetPreview,
+                    nextSetPreviewError: viewModel.nextSetPreviewError,
+                    isLoadingNextSetPreview: viewModel.isLoadingNextSetPreview,
+                    onRetryNextSetPreview: { Task { await viewModel.loadNextSetPreview() } }
                 )
             } else if let exercise = viewModel.currentExercise {
                 WorkoutTrainModeScreen(
diff --git a/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionView.swift b/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionView.swift
index 5befc8e..657c1ad 100644
--- a/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionView.swift
+++ b/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionView.swift
@@ -52,7 +52,8 @@ struct WorkoutSessionView: View {
                 historyStore: historyStore,
                 previousRecordService: Self.makePreviousRecordService(),
                 serverWorkoutID: serverWorkoutID,
-                progressService: serverWorkoutID == nil ? nil : Self.makeProgressService()
+                progressService: serverWorkoutID == nil ? nil : Self.makeProgressService(),
+                nextSetService: serverWorkoutID == nil ? nil : Self.makeWorkoutReadService()
             )
         )
         self.historyStore = historyStore
diff --git a/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionViewModel.swift b/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionViewModel.swift
index 0d00302..eaa1359 100644
--- a/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionViewModel.swift
+++ b/GYMUP/Sources/Features/WorkoutSession/WorkoutSessionViewModel.swift
@@ -13,9 +13,13 @@ final class WorkoutSessionViewModel {
     private let historyStore: HistoryStore
     private let goalSettings: OnboardingStoredSettings?
     private let previousRecordService: ExerciseReadAPIService?
+    let nextSetService: WorkoutNextSetReading?
     let progressService: WorkoutSessionProgressing?
     private(set) var previousRecordErrors: [String: String] = [:]
     private(set) var loadingPreviousRecordExerciseIDs: Set<String> = []
+    private(set) var nextSetPreview: NextWorkoutSetResponse?
+    private(set) var nextSetPreviewError: String?
+    private(set) var isLoadingNextSetPreview = false
     var isSubmittingWorkoutAction = false
     var serverActionErrorMessage: String?
     var failedServerAction: FailedWorkoutServerAction?
@@ -40,7 +44,8 @@ final class WorkoutSessionViewModel {
         historyStore: HistoryStore? = nil,
         goalSettings: OnboardingStoredSettings? = .load(),
         previousRecordService: ExerciseReadAPIService? = nil,
-        progressService: WorkoutSessionProgressing? = nil
+        progressService: WorkoutSessionProgressing? = nil,
+        nextSetService: WorkoutNextSetReading? = nil
     ) {
         plan = .sample(for: routineID)
         self.startedAt = startsImmediately ? startedAt : nil
@@ -49,6 +54,7 @@ final class WorkoutSessionViewModel {
         self.goalSettings = goalSettings
         self.previousRecordService = previousRecordService
         self.progressService = progressService
+        self.nextSetService = nextSetService
         serverWorkoutID = nil
     }
 
@@ -60,7 +66,8 @@ final class WorkoutSessionViewModel {
         goalSettings: OnboardingStoredSettings? = .load(),
         previousRecordService: ExerciseReadAPIService? = nil,
         serverWorkoutID: String? = nil,
-        progressService: WorkoutSessionProgressing? = nil
+        progressService: WorkoutSessionProgressing? = nil,
+        nextSetService: WorkoutNextSetReading? = nil
     ) {
         self.plan = plan
         self.startedAt = startsImmediately ? startedAt : nil
@@ -70,6 +77,7 @@ final class WorkoutSessionViewModel {
         self.previousRecordService = previousRecordService
         self.serverWorkoutID = serverWorkoutID
         self.progressService = progressService
+        self.nextSetService = nextSetService
     }
 
     var isPaused: Bool { pausedAt != nil }
@@ -305,3 +313,63 @@ extension WorkoutSessionViewModel {
         }
     }
 }
+
+extension WorkoutSessionViewModel {
+    func loadNextSetPreview() async {
+        guard !isLoadingNextSetPreview,
+              isServerManagedRest,
+              let workoutID = serverWorkoutID,
+              let nextSetService,
+              let exercise = currentExercise,
+              exercise.measure == .repetitions,
+              let localSetIndex = currentSetIndex else { return }
+
+        let expectedSetIndex = localSetIndex + 1
+        isLoadingNextSetPreview = true
+        nextSetPreview = nil
+        nextSetPreviewError = nil
+        defer { isLoadingNextSetPreview = false }
+
+        do {
+            let response = try await nextSetService.nextSet(workoutId: workoutID)
+            guard isCurrentNextSetRequest(
+                workoutID: workoutID,
+                exerciseID: exercise.id,
+                setIndex: localSetIndex
+            ) else { return }
+            guard response.exerciseId == exercise.id,
+                  response.setIndex == expectedSetIndex,
+                  !response.exerciseName.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty,
+                  response.weight.isFinite,
+                  response.weight >= 0,
+                  response.reps >= 0 else {
+                throw APIClientError.invalidResponse
+            }
+
+            nextSetPreview = response
+        } catch {
+            guard !Task.isCancelled,
+                  isCurrentNextSetRequest(
+                    workoutID: workoutID,
+                    exerciseID: exercise.id,
+                    setIndex: localSetIndex
+                  ) else { return }
+            nextSetPreviewError = Self.nextSetPreviewMessage(for: error)
+        }
+    }
+
+    private func isCurrentNextSetRequest(workoutID: String, exerciseID: String, setIndex: Int) -> Bool {
+        serverWorkoutID == workoutID &&
+            isServerManagedRest &&
+            currentExercise?.id == exerciseID &&
+            currentSetIndex == setIndex
+    }
+
+    private static func nextSetPreviewMessage(for error: Error) -> String {
+        if let apiError = error as? APIClientError,
+           case let .server(_, detail) = apiError {
+            return detail.message
+        }
+        return "다음 세트 정보를 불러오지 못했어요."
+    }
+}
diff --git a/GYMUP/Sources/Networking/DebugOnboardingNetworking.swift b/GYMUP/Sources/Networking/DebugOnboardingNetworking.swift
index d4136ac..634ac83 100644
--- a/GYMUP/Sources/Networking/DebugOnboardingNetworking.swift
+++ b/GYMUP/Sources/Networking/DebugOnboardingNetworking.swift
@@ -179,5 +179,17 @@ enum DebugOnboardingNetworking {
         let client = APIClient(environment: environment, tokenProvider: tokenProvider)
         return WorkoutSessionAPIService(client: client)
     }
+
+    static func makeWorkoutReadService() -> WorkoutReadAPIService? {
+        guard let baseURL = URL(string: "http://localhost:8000"),
+              let environment = try? APIEnvironment(baseURL: baseURL)
+        else {
+            return nil
+        }
+
+        let tokenProvider = DevelopmentBearerTokenProvider(environment: environment)
+        let client = APIClient(environment: environment, tokenProvider: tokenProvider)
+        return WorkoutReadAPIService(client: client)
+    }
 }
 #endif
diff --git a/GYMUP/Sources/Networking/WorkoutReadAPIService.swift b/GYMUP/Sources/Networking/WorkoutReadAPIService.swift
index a6c2c84..75c23d1 100644
--- a/GYMUP/Sources/Networking/WorkoutReadAPIService.swift
+++ b/GYMUP/Sources/Networking/WorkoutReadAPIService.swift
@@ -41,7 +41,11 @@ struct NextWorkoutSetResponse: Codable, Equatable {
     let restEndsAt: String
 }
 
-struct WorkoutReadAPIService {
+protocol WorkoutNextSetReading {
+    func nextSet(workoutId: String) async throws -> NextWorkoutSetResponse
+}
+
+struct WorkoutReadAPIService: WorkoutNextSetReading {
     private let client: APIClient
 
     init(client: APIClient) {
diff --git a/GYMUP/Tests/WorkoutSessionNextSetPreviewTests.swift b/GYMUP/Tests/WorkoutSessionNextSetPreviewTests.swift
new file mode 100644
index 0000000..953a462
--- /dev/null
+++ b/GYMUP/Tests/WorkoutSessionNextSetPreviewTests.swift
@@ -0,0 +1,143 @@
+import XCTest
+@testable import GYMUP
+
+final class WorkoutSessionNextSetPreviewTests: XCTestCase {
+    @MainActor
+    func testPreviewUsesValidatedServerValuesAndKeepsLocalPlanUnchanged() async throws {
+        let start = Date(timeIntervalSince1970: 1_800_000_000)
+        let service = MockWorkoutSessionRestService(startDate: start)
+        service.nextSetResponse = NextWorkoutSetResponse(
+            exerciseId: "exercise-1",
+            exerciseName: "Bench Press",
+            setIndex: 2,
+            weight: 47.5,
+            reps: 6,
+            restEndsAt: "not-used-by-preview"
+        )
+        let viewModel = makeViewModel(service: service, start: start)
+        let didComplete = await viewModel.completeSet(exerciseIndex: 0, setIndex: 0, at: start)
+        XCTAssertTrue(didComplete)
+
+        await viewModel.loadNextSetPreview()
+
+        XCTAssertEqual(service.nextSetRequests, ["workout-1"])
+        XCTAssertEqual(viewModel.nextSetPreview?.exerciseName, "Bench Press")
+        XCTAssertEqual(viewModel.nextSetPreview?.setIndex, 2)
+        XCTAssertEqual(viewModel.nextSetPreview?.weight, 47.5)
+        XCTAssertEqual(viewModel.nextSetPreview?.reps, 6)
+        XCTAssertNil(viewModel.nextSetPreviewError)
+        XCTAssertEqual(viewModel.currentExercise?.sets[1].weightKilograms, 42.5)
+        XCTAssertEqual(viewModel.currentExercise?.sets[1].repetitions, 8)
+        XCTAssertEqual(viewModel.currentSetIndex, 1)
+    }
+
+    @MainActor
+    func testPreviewFailureKeepsLocalFallbackAndRetryLoadsServerValues() async throws {
+        let start = Date(timeIntervalSince1970: 1_800_000_000)
+        let service = MockWorkoutSessionRestService(startDate: start)
+        service.nextSetError = serverError(message: "서버 미리보기 오류")
+        let viewModel = makeViewModel(service: service, start: start)
+        let didComplete = await viewModel.completeSet(exerciseIndex: 0, setIndex: 0, at: start)
+        XCTAssertTrue(didComplete)
+
+        await viewModel.loadNextSetPreview()
+
+        XCTAssertNil(viewModel.nextSetPreview)
+        XCTAssertEqual(viewModel.nextSetPreviewError, "서버 미리보기 오류")
+        XCTAssertEqual(viewModel.currentExercise?.sets[1].weightKilograms, 42.5)
+        XCTAssertEqual(viewModel.currentExercise?.sets[1].repetitions, 8)
+
+        service.nextSetResponse = nextSetResponse()
+        await viewModel.loadNextSetPreview()
+
+        XCTAssertEqual(service.nextSetRequests, ["workout-1", "workout-1"])
+        XCTAssertEqual(viewModel.nextSetPreview?.weight, 47.5)
+        XCTAssertNil(viewModel.nextSetPreviewError)
+    }
+
+    @MainActor
+    func testPreviewRejectsExerciseOrSetIndexMismatch() async throws {
+        let start = Date(timeIntervalSince1970: 1_800_000_000)
+        let service = MockWorkoutSessionRestService(startDate: start)
+        service.nextSetResponse = nextSetResponse(setIndex: 3)
+        let viewModel = makeViewModel(service: service, start: start)
+        let didComplete = await viewModel.completeSet(exerciseIndex: 0, setIndex: 0, at: start)
+        XCTAssertTrue(didComplete)
+
+        await viewModel.loadNextSetPreview()
+
+        XCTAssertNil(viewModel.nextSetPreview)
+        XCTAssertEqual(viewModel.nextSetPreviewError, "다음 세트 정보를 불러오지 못했어요.")
+        XCTAssertEqual(viewModel.currentSetIndex, 1)
+
+        service.nextSetResponse = nextSetResponse(exerciseID: "exercise-2")
+        await viewModel.loadNextSetPreview()
+
+        XCTAssertNil(viewModel.nextSetPreview)
+        XCTAssertEqual(viewModel.nextSetPreviewError, "다음 세트 정보를 불러오지 못했어요.")
+        XCTAssertEqual(service.nextSetRequests.count, 2)
+    }
+
+    @MainActor
+    private func makeViewModel(
+        service: MockWorkoutSessionRestService,
+        start: Date
+    ) -> WorkoutSessionViewModel {
+        let currentExercise = WorkoutSessionExercise(
+            id: "exercise-1",
+            name: "벤치 프레스",
+            target: "가슴",
+            restDurationSeconds: 75,
+            formSteps: [],
+            beginnerTip: "",
+            sets: [
+                WorkoutSessionSet(weightKilograms: 40, repetitions: 8),
+                WorkoutSessionSet(weightKilograms: 42.5, repetitions: 8)
+            ]
+        )
+        let nextExercise = WorkoutSessionExercise(
+            id: "exercise-2",
+            name: "로우",
+            target: "등",
+            restDurationSeconds: 60,
+            formSteps: [],
+            beginnerTip: "",
+            sets: [WorkoutSessionSet(weightKilograms: 30, repetitions: 10)]
+        )
+        let plan = WorkoutSessionPlan(
+            id: "routine-1",
+            name: "루틴",
+            title: "루틴",
+            estimatedDurationMinutes: 20,
+            exercises: [currentExercise, nextExercise]
+        )
+        return WorkoutSessionViewModel(
+            plan: plan,
+            startedAt: start,
+            serverWorkoutID: "workout-1",
+            progressService: service,
+            nextSetService: service
+        )
+    }
+
+    private func nextSetResponse(
+        exerciseID: String = "exercise-1",
+        setIndex: Int = 2
+    ) -> NextWorkoutSetResponse {
+        NextWorkoutSetResponse(
+            exerciseId: exerciseID,
+            exerciseName: "Bench Press",
+            setIndex: setIndex,
+            weight: 47.5,
+            reps: 6,
+            restEndsAt: ""
+        )
+    }
+
+    private func serverError(message: String) -> APIClientError {
+        .server(
+            statusCode: 503,
+            detail: ServerErrorDetail(code: "TEMPORARY_FAILURE", message: message)
+        )
+    }
+}
diff --git a/GYMUP/Tests/WorkoutSessionServerRestTestSupport.swift b/GYMUP/Tests/WorkoutSessionServerRestTestSupport.swift
index 0b88881..98583fd 100644
--- a/GYMUP/Tests/WorkoutSessionServerRestTestSupport.swift
+++ b/GYMUP/Tests/WorkoutSessionServerRestTestSupport.swift
@@ -2,7 +2,7 @@ import Foundation
 @testable import GYMUP
 
 @MainActor
-final class MockWorkoutSessionRestService: WorkoutSessionProgressing {
+final class MockWorkoutSessionRestService: WorkoutSessionProgressing, WorkoutNextSetReading {
     struct SetRequest {
         let workoutId: String
         let request: CreateWorkoutSetRequest
@@ -17,6 +17,7 @@ final class MockWorkoutSessionRestService: WorkoutSessionProgressing {
     var setRequests: [SetRequest] = []
     var restRequests: [RestRequest] = []
     var currentRestRequests: [String] = []
+    var nextSetRequests: [String] = []
     var skipRequests: [String] = []
     var extendRequests: [(String, Int)] = []
     var nextRestStartError: Error?
@@ -26,6 +27,8 @@ final class MockWorkoutSessionRestService: WorkoutSessionProgressing {
     var restStartCommitsBeforeThrow = false
     var currentRestResponse: CurrentRestResponse?
     var nextExtendResponse: ExtendCurrentRestResponse?
+    var nextSetResponse: NextWorkoutSetResponse?
+    var nextSetError: Error?
     private let startDate: Date
 
     init(startDate: Date) {
@@ -86,6 +89,16 @@ final class MockWorkoutSessionRestService: WorkoutSessionProgressing {
         return currentRestResponse
     }
 
+    func nextSet(workoutId: String) async throws -> NextWorkoutSetResponse {
+        nextSetRequests.append(workoutId)
+        if let error = nextSetError {
+            nextSetError = nil
+            throw error
+        }
+        guard let nextSetResponse else { throw APIClientError.invalidResponse }
+        return nextSetResponse
+    }
+
     func skipCurrentRest(workoutId: String) async throws -> SkipCurrentRestResponse {
         skipRequests.append(workoutId)
         if let error = nextSkipError {
diff --git a/GYMUP/Tests/WorkoutSessionServerRestTests.swift b/GYMUP/Tests/WorkoutSessionServerRestTests.swift
index 749d033..4f6589d 100644
--- a/GYMUP/Tests/WorkoutSessionServerRestTests.swift
+++ b/GYMUP/Tests/WorkoutSessionServerRestTests.swift
@@ -225,6 +225,11 @@ final class WorkoutSessionServerRestTests: XCTestCase {
         XCTAssertFalse(viewModel.isServerManagedRest)
         XCTAssertTrue(service.setRequests.isEmpty)
         XCTAssertTrue(service.restRequests.isEmpty)
+
+        await viewModel.loadNextSetPreview()
+
+        XCTAssertTrue(service.nextSetRequests.isEmpty)
+        XCTAssertNil(viewModel.nextSetPreviewError)
     }
 
     @MainActor
@@ -269,7 +274,8 @@ final class WorkoutSessionServerRestTests: XCTestCase {
             plan: plan,
             startedAt: start,
             serverWorkoutID: "workout-1",
-            progressService: service
+            progressService: service,
+            nextSetService: service
         )
     }