diff --git a/ios/App/App/CoachWorkoutObserver.swift b/ios/App/App/CoachWorkoutObserver.swift
new file mode 100644
index 0000000..54b13de
--- /dev/null
+++ b/ios/App/App/CoachWorkoutObserver.swift
@@ -0,0 +1,212 @@
+// CoachWorkoutObserver.swift
+// Observer HealthKit en background : détecte les nouveaux HKWorkout
+// ajoutés au store (= fin de séance Apple Watch ou autre source) et
+// push une notif locale enrichie sur l'iPhone.
+//
+// Pipeline :
+//   1. requestAuthorization (lecture HKWorkout)
+//   2. enableBackgroundDelivery(.immediate) sur HKWorkoutType
+//   3. HKObserverQuery → callback à chaque nouveau workout (réveille
+//      l'app en background même si fermée)
+//   4. fetchLatestWorkout → query le dernier workout sur la dernière
+//      heure pour récupérer durée/kcal/distance
+//   5. scheduleNotification → UNNotificationRequest immédiat
+//
+// Usage JS :
+//   await window.Capacitor.Plugins.CoachWorkoutObserver.startObserving()
+//     → { observing: true }
+//   await window.Capacitor.Plugins.CoachWorkoutObserver.stopObserving()
+//     → { observing: false }
+//
+// Capability Xcode requise : Signing & Capabilities → HealthKit →
+// cocher "Background Delivery". Sans ça, iOS ne réveille pas l'app.
+
+import Foundation
+import Capacitor
+import HealthKit
+import UserNotifications
+
+@objc(CoachWorkoutObserverPlugin)
+public class CoachWorkoutObserverPlugin: CAPPlugin, CAPBridgedPlugin {
+    public let identifier = "CoachWorkoutObserverPlugin"
+    public let jsName = "CoachWorkoutObserver"
+    public let pluginMethods: [CAPPluginMethod] = [
+        CAPPluginMethod(name: "startObserving", returnType: CAPPluginReturnPromise),
+        CAPPluginMethod(name: "stopObserving", returnType: CAPPluginReturnPromise),
+    ]
+
+    private let healthStore = HKHealthStore()
+    private var observerQuery: HKObserverQuery?
+
+    // Clé UserDefaults pour persister l'UUID du dernier workout notifié.
+    // Évite les doublons si iOS appelle l'observer plusieurs fois pour
+    // le même workout (ce qui arrive).
+    private let lastNotifiedKey = "CoachWorkoutObserver.lastNotifiedUUID"
+
+    @objc func startObserving(_ call: CAPPluginCall) {
+        guard HKHealthStore.isHealthDataAvailable() else {
+            call.reject("HealthKit not available on this device")
+            return
+        }
+        Task {
+            do {
+                try await requestPermissionsIfNeeded()
+                try await enableBackgroundDelivery()
+                startObserverQuery()
+                call.resolve(["observing": true])
+            } catch {
+                call.reject("Observer setup failed: \(error.localizedDescription)")
+            }
+        }
+    }
+
+    @objc func stopObserving(_ call: CAPPluginCall) {
+        if let q = observerQuery {
+            healthStore.stop(q)
+            observerQuery = nil
+        }
+        let workoutType = HKObjectType.workoutType()
+        healthStore.disableBackgroundDelivery(for: workoutType) { _, _ in }
+        call.resolve(["observing": false])
+    }
+
+    // MARK: - HealthKit setup
+
+    private func requestPermissionsIfNeeded() async throws {
+        let workoutType = HKObjectType.workoutType()
+        try await withCheckedThrowingContinuation { (cont: CheckedContinuation<Void, Error>) in
+            healthStore.requestAuthorization(toShare: nil, read: [workoutType]) { _, error in
+                if let error = error {
+                    cont.resume(throwing: error)
+                } else {
+                    cont.resume()
+                }
+            }
+        }
+    }
+
+    private func enableBackgroundDelivery() async throws {
+        let workoutType = HKObjectType.workoutType()
+        try await withCheckedThrowingContinuation { (cont: CheckedContinuation<Void, Error>) in
+            healthStore.enableBackgroundDelivery(for: workoutType, frequency: .immediate) { ok, error in
+                if let error = error {
+                    cont.resume(throwing: error)
+                } else {
+                    NSLog("[CoachWorkoutObserver] background delivery enabled=%@", ok ? "true" : "false")
+                    cont.resume()
+                }
+            }
+        }
+    }
+
+    private func startObserverQuery() {
+        // Stop l'ancienne au cas où startObserving est rappelé (idempotent)
+        if let q = observerQuery {
+            healthStore.stop(q)
+        }
+        let workoutType = HKObjectType.workoutType()
+        let query = HKObserverQuery(sampleType: workoutType, predicate: nil) { [weak self] _, completion, error in
+            if let error = error {
+                NSLog("[CoachWorkoutObserver] query error: %@", error.localizedDescription)
+                completion()
+                return
+            }
+            NSLog("[CoachWorkoutObserver] observer fired")
+            self?.fetchLatestWorkout {
+                completion()  // signaler iOS qu'on a fini de traiter (mandatory)
+            }
+        }
+        healthStore.execute(query)
+        observerQuery = query
+        NSLog("[CoachWorkoutObserver] observer query started")
+    }
+
+    // MARK: - Fetch + notif
+
+    private func fetchLatestWorkout(completion: @escaping () -> Void) {
+        let workoutType = HKObjectType.workoutType()
+        // Filtre 1h pour limiter le scope (un workout très ancien remonté
+        // par un sync HealthKit tardif ne devrait pas spammer une notif).
+        let pred = HKQuery.predicateForSamples(withStart: Date(timeIntervalSinceNow: -3600), end: nil)
+        let sort = NSSortDescriptor(key: HKSampleSortIdentifierEndDate, ascending: false)
+        let query = HKSampleQuery(
+            sampleType: workoutType,
+            predicate: pred,
+            limit: 1,
+            sortDescriptors: [sort]
+        ) { [weak self] _, samples, error in
+            defer { completion() }
+            guard let self = self else { return }
+            if let error = error {
+                NSLog("[CoachWorkoutObserver] sample query error: %@", error.localizedDescription)
+                return
+            }
+            guard let workout = samples?.first as? HKWorkout else {
+                NSLog("[CoachWorkoutObserver] no workout in last hour")
+                return
+            }
+            let uuid = workout.uuid.uuidString
+            let lastUuid = UserDefaults.standard.string(forKey: self.lastNotifiedKey) ?? ""
+            if uuid == lastUuid {
+                NSLog("[CoachWorkoutObserver] workout %@ already notified, skip", uuid)
+                return
+            }
+            UserDefaults.standard.set(uuid, forKey: self.lastNotifiedKey)
+            self.scheduleNotification(for: workout)
+        }
+        healthStore.execute(query)
+    }
+
+    private func scheduleNotification(for workout: HKWorkout) {
+        let durationMin = Int(workout.duration / 60)
+        var bodyParts: [String] = ["\(durationMin) min"]
+        if let kcal = workout.totalEnergyBurned?.doubleValue(for: .kilocalorie()), kcal > 0 {
+            bodyParts.append("\(Int(kcal)) kcal")
+        }
+        if let dist = workout.totalDistance?.doubleValue(for: .meter()), dist > 100 {
+            let km = dist / 1000
+            bodyParts.append(String(format: "%.1f km", km))
+        }
+        let typeName = workoutActivityName(workout.workoutActivityType)
+        let body = bodyParts.joined(separator: " · ")
+
+        let content = UNMutableNotificationContent()
+        content.title = "🎉 Séance \(typeName) terminée"
+        content.body = "Bravo ! \(body)"
+        content.sound = .default
+
+        let request = UNNotificationRequest(
+            identifier: "coach_workout_done_\(workout.uuid.uuidString)",
+            content: content,
+            trigger: nil  // déclenchement immédiat
+        )
+        UNUserNotificationCenter.current().add(request) { error in
+            if let error = error {
+                NSLog("[CoachWorkoutObserver] notif scheduling failed: %@", error.localizedDescription)
+            } else {
+                NSLog("[CoachWorkoutObserver] notif scheduled for workout %@", workout.uuid.uuidString)
+            }
+        }
+    }
+
+    private func workoutActivityName(_ activity: HKWorkoutActivityType) -> String {
+        switch activity {
+        case .running: return "course"
+        case .cycling: return "vélo"
+        case .walking: return "marche"
+        case .hiking: return "rando"
+        case .swimming: return "natation"
+        case .functionalStrengthTraining, .traditionalStrengthTraining: return "renfo"
+        case .coreTraining: return "gainage"
+        case .yoga: return "yoga"
+        case .pilates: return "pilates"
+        case .flexibility: return "mobilité"
+        case .highIntensityIntervalTraining: return "HIIT"
+        case .crossTraining: return "cross-training"
+        case .rowing: return "aviron"
+        case .skatingSports: return "patinage"
+        case .paddleSports: return "paddle"
+        default: return "sport"
+        }
+    }
+}
diff --git a/ios/App/App/MainViewController.swift b/ios/App/App/MainViewController.swift
index 257642b..aca0510 100644
--- a/ios/App/App/MainViewController.swift
+++ b/ios/App/App/MainViewController.swift
@@ -15,6 +15,9 @@ class MainViewController: CAPBridgeViewController {
         // Plugin natif route GPS HealthKit — récupère la trace des workouts
         // Apple Watch (HKWorkoutRouteQuery, cf. CoachHealthRoute.swift).
         bridge?.registerPluginInstance(CoachHealthRoutePlugin())
+        // Plugin natif observer HealthKit — détecte fin de séance Watch et
+        // push notif locale "🎉 Séance terminée" (cf. CoachWorkoutObserver.swift).
+        bridge?.registerPluginInstance(CoachWorkoutObserverPlugin())
     }
 
     override func viewDidLoad() {