diff --git a/contrib/resourcetuner/resourcetuner.go b/contrib/resourcetuner/resourcetuner.go
index a52a53e28..302af9cb7 100644
--- a/contrib/resourcetuner/resourcetuner.go
+++ b/contrib/resourcetuner/resourcetuner.go
@@ -77,11 +77,14 @@ func NewResourceBasedTuner(opts ResourceBasedTunerOptions) (worker.WorkerTuner,
 	}
 	nexusSS := &ResourceBasedSlotSupplier{controller: controller,
 		options: defaultWorkflowResourceBasedSlotSupplierOptions()}
+	sessSS := &ResourceBasedSlotSupplier{controller: controller,
+		options: defaultActivityResourceBasedSlotSupplierOptions()}
 	compositeTuner, err := worker.NewCompositeTuner(worker.CompositeTunerOptions{
-		WorkflowSlotSupplier:      wfSS,
-		ActivitySlotSupplier:      actSS,
-		LocalActivitySlotSupplier: laSS,
-		NexusSlotSupplier:         nexusSS,
+		WorkflowSlotSupplier:        wfSS,
+		ActivitySlotSupplier:        actSS,
+		LocalActivitySlotSupplier:   laSS,
+		NexusSlotSupplier:           nexusSS,
+		SessionActivitySlotSupplier: sessSS,
 	})
 	if err != nil {
 		return nil, err
diff --git a/internal/internal_worker.go b/internal/internal_worker.go
index 61f324f91..288e2f665 100644
--- a/internal/internal_worker.go
+++ b/internal/internal_worker.go
@@ -399,7 +399,7 @@ func (ww *workflowWorker) Stop() {
 	ww.worker.Stop()
 }
 
-func newSessionWorker(service workflowservice.WorkflowServiceClient, params workerExecutionParameters, overrides *workerOverrides, env *registry, maxConcurrentSessionExecutionSize int) *sessionWorker {
+func newSessionWorker(service workflowservice.WorkflowServiceClient, params workerExecutionParameters, env *registry, maxConcurrentSessionExecutionSize int) *sessionWorker {
 	if params.Identity == "" {
 		params.Identity = getWorkerIdentity(params.TaskQueue)
 	}
@@ -412,15 +412,14 @@ func newSessionWorker(service workflowservice.WorkflowServiceClient, params work
 	creationTaskqueue := getCreationTaskqueue(params.TaskQueue)
 	params.UserContext = context.WithValue(params.UserContext, sessionEnvironmentContextKey, sessionEnvironment)
 	params.TaskQueue = sessionEnvironment.GetResourceSpecificTaskqueue()
-	activityWorker := newActivityWorker(service, params, overrides, env, nil)
+	activityWorker := newActivityWorker(service, params,
+		&workerOverrides{slotSupplier: params.Tuner.GetSessionActivitySlotSupplier()}, env, nil)
 
 	params.MaxConcurrentActivityTaskQueuePollers = 1
 	params.TaskQueue = creationTaskqueue
-	if overrides == nil {
-		overrides = &workerOverrides{}
-	}
 	// Although we have session token bucket to limit session size across creation
 	// and recreation, we also limit it here for creation only
+	overrides := &workerOverrides{}
 	overrides.slotSupplier, _ = NewFixedSizeSlotSupplier(maxConcurrentSessionExecutionSize)
 	creationWorker := newActivityWorker(service, params, overrides, env, sessionEnvironment.GetTokenBucket())
 
@@ -1758,7 +1757,7 @@ func NewAggregatedWorker(client *WorkflowClient, taskQueue string, options Worke
 
 	var sessionWorker *sessionWorker
 	if options.EnableSessionWorker && !options.LocalActivityWorkerOnly {
-		sessionWorker = newSessionWorker(client.workflowService, workerParams, nil, registry, options.MaxConcurrentSessionExecutionSize)
+		sessionWorker = newSessionWorker(client.workflowService, workerParams, registry, options.MaxConcurrentSessionExecutionSize)
 		registry.RegisterActivityWithOptions(sessionCreationActivity, RegisterActivityOptions{
 			Name: sessionCreationActivityName,
 		})
diff --git a/internal/tuning.go b/internal/tuning.go
index faf490475..3a36efe62 100644
--- a/internal/tuning.go
+++ b/internal/tuning.go
@@ -46,6 +46,8 @@ type WorkerTuner interface {
 	GetLocalActivitySlotSupplier() SlotSupplier
 	// GetNexusSlotSupplier returns the SlotSupplier used for nexus tasks.
 	GetNexusSlotSupplier() SlotSupplier
+	// GetSessionActivitySlotSupplier returns the SlotSupplier used for activities within sessions.
+	GetSessionActivitySlotSupplier() SlotSupplier
 }
 
 // SlotPermit is a permit to use a slot.
@@ -150,10 +152,11 @@ type SlotSupplier interface {
 //
 // WARNING: Custom implementations of SlotSupplier are currently experimental.
 type CompositeTuner struct {
-	workflowSlotSupplier      SlotSupplier
-	activitySlotSupplier      SlotSupplier
-	localActivitySlotSupplier SlotSupplier
-	nexusSlotSupplier         SlotSupplier
+	workflowSlotSupplier        SlotSupplier
+	activitySlotSupplier        SlotSupplier
+	localActivitySlotSupplier   SlotSupplier
+	nexusSlotSupplier           SlotSupplier
+	sessionActivitySlotSupplier SlotSupplier
 }
 
 func (c *CompositeTuner) GetWorkflowTaskSlotSupplier() SlotSupplier {
@@ -168,6 +171,9 @@ func (c *CompositeTuner) GetLocalActivitySlotSupplier() SlotSupplier {
 func (c *CompositeTuner) GetNexusSlotSupplier() SlotSupplier {
 	return c.nexusSlotSupplier
 }
+func (c *CompositeTuner) GetSessionActivitySlotSupplier() SlotSupplier {
+	return c.sessionActivitySlotSupplier
+}
 
 // CompositeTunerOptions are the options used by NewCompositeTuner.
 type CompositeTunerOptions struct {
@@ -179,6 +185,8 @@ type CompositeTunerOptions struct {
 	LocalActivitySlotSupplier SlotSupplier
 	// NexusSlotSupplier is the SlotSupplier used for nexus tasks.
 	NexusSlotSupplier SlotSupplier
+	// SessionActivitySlotSupplier is the SlotSupplier used for activities within sessions.
+	SessionActivitySlotSupplier SlotSupplier
 }
 
 // NewCompositeTuner creates a WorkerTuner that uses a combination of slot suppliers.
@@ -186,10 +194,11 @@ type CompositeTunerOptions struct {
 // WARNING: Custom implementations of SlotSupplier are currently experimental.
 func NewCompositeTuner(options CompositeTunerOptions) (WorkerTuner, error) {
 	return &CompositeTuner{
-		workflowSlotSupplier:      options.WorkflowSlotSupplier,
-		activitySlotSupplier:      options.ActivitySlotSupplier,
-		localActivitySlotSupplier: options.LocalActivitySlotSupplier,
-		nexusSlotSupplier:         options.NexusSlotSupplier,
+		workflowSlotSupplier:        options.WorkflowSlotSupplier,
+		activitySlotSupplier:        options.ActivitySlotSupplier,
+		localActivitySlotSupplier:   options.LocalActivitySlotSupplier,
+		nexusSlotSupplier:           options.NexusSlotSupplier,
+		sessionActivitySlotSupplier: options.SessionActivitySlotSupplier,
 	}, nil
 }
 
@@ -235,11 +244,16 @@ func NewFixedSizeTuner(options FixedSizeTunerOptions) (WorkerTuner, error) {
 	if err != nil {
 		return nil, err
 	}
+	sessSS, err := NewFixedSizeSlotSupplier(options.NumActivitySlots)
+	if err != nil {
+		return nil, err
+	}
 	return &CompositeTuner{
-		workflowSlotSupplier:      wfSS,
-		activitySlotSupplier:      actSS,
-		localActivitySlotSupplier: laSS,
-		nexusSlotSupplier:         nexusSS,
+		workflowSlotSupplier:        wfSS,
+		activitySlotSupplier:        actSS,
+		localActivitySlotSupplier:   laSS,
+		nexusSlotSupplier:           nexusSS,
+		sessionActivitySlotSupplier: sessSS,
 	}, nil
 }
 
diff --git a/test/integration_test.go b/test/integration_test.go
index 4a3fcad9b..bf6b48df2 100644
--- a/test/integration_test.go
+++ b/test/integration_test.go
@@ -274,6 +274,11 @@ func (ts *IntegrationTestSuite) SetupTest() {
 		ts.NoError(err)
 		options.Tuner = tuner
 	}
+	if strings.Contains(ts.T().Name(), "SlotSuppliersWithSession") {
+		options.MaxConcurrentActivityExecutionSize = 1
+		// Apparently this is on by default in these tests anyway, but to be explicit
+		options.EnableSessionWorker = true
+	}
 
 	ts.worker = worker.New(ts.client, ts.taskQueueName, options)
 	ts.workerStopped = false
@@ -3269,6 +3274,27 @@ func (ts *IntegrationTestSuite) TestResourceBasedSlotSupplierManyActs() {
 	ts.assertMetricGaugeEventually(metrics.WorkerTaskSlotsUsed, wfWorkertags, 0)
 }
 
+func (ts *IntegrationTestSuite) TestSlotSuppliersWithSessionAndOneConcurrentMax() {
+	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Minute)
+	defer cancel()
+
+	// Activities time out without the fix, since obtaining a slot takes too long
+	wfRuns := make([]client.WorkflowRun, 0)
+	for i := 0; i < 3; i++ {
+		opts := ts.startWorkflowOptions("slot-suppliers-with-session" + strconv.Itoa(i))
+		opts.WorkflowExecutionTimeout = 1 * time.Minute
+		run, err := ts.client.ExecuteWorkflow(ctx, opts, ts.workflows.Echo, "hi")
+		ts.NoError(err)
+		ts.NotNil(run)
+		ts.NoError(err)
+		wfRuns = append(wfRuns, run)
+	}
+
+	for _, run := range wfRuns {
+		ts.NoError(run.Get(ctx, nil))
+	}
+}
+
 func (ts *IntegrationTestSuite) TestTooFewParams() {
 	var res ParamsValue
 	// Only give first param