diff --git a/ipn/backend.go b/ipn/backend.go
index 51617e08e..32b38200a 100644
--- a/ipn/backend.go
+++ b/ipn/backend.go
@@ -90,7 +90,8 @@ const (
 
 	// NotifyPeerChanges, if set, causes netmap delta updates to be sent as [tailcfg.PeerChange] rather than a full NetMap.
 	// Full netmap responses from the control plane are still sent as a full NetMap.  PeerChanges are only sent to sessions
-	// that have opted in to this mode.
+	// that have opted in to this mode.   Setting this flag also implies NotifyInitialNetMap, as the first message must
+	// contain a full netmap to establish the baseline for future peer changes.
 	NotifyPeerChanges NotifyWatchOpt = 1 << 12
 )
 
diff --git a/ipn/ipnlocal/local.go b/ipn/ipnlocal/local.go
index 7432e33a7..d6aee5da1 100644
--- a/ipn/ipnlocal/local.go
+++ b/ipn/ipnlocal/local.go
@@ -3296,7 +3296,7 @@ func (b *LocalBackend) WatchNotificationsAs(ctx context.Context, actor ipnauth.A
 
 	b.mu.Lock()
 
-	const initialBits = ipn.NotifyInitialState | ipn.NotifyInitialPrefs | ipn.NotifyInitialNetMap | ipn.NotifyInitialDriveShares | ipn.NotifyInitialSuggestedExitNode | ipn.NotifyInitialClientVersion
+	const initialBits = ipn.NotifyInitialState | ipn.NotifyInitialPrefs | ipn.NotifyInitialNetMap | ipn.NotifyInitialDriveShares | ipn.NotifyInitialSuggestedExitNode | ipn.NotifyInitialClientVersion | ipn.NotifyPeerChanges
 	if mask&initialBits != 0 {
 		cn := b.currentNode()
 		ini = &ipn.Notify{Version: version.Long()}
@@ -3310,7 +3310,10 @@ func (b *LocalBackend) WatchNotificationsAs(ctx context.Context, actor ipnauth.A
 		if mask&ipn.NotifyInitialPrefs != 0 {
 			ini.Prefs = new(b.sanitizedPrefsLocked())
 		}
-		if mask&ipn.NotifyInitialNetMap != 0 {
+		if mask&(ipn.NotifyInitialNetMap|ipn.NotifyPeerChanges) != 0 {
+			// Include the initial NetMap if explicitly requested, or if the
+			// client subscribes to peer change deltas. Deltas are useless
+			// without a base netmap to apply them to.
 			ini.NetMap = cn.NetMap()
 		}
 		if mask&ipn.NotifyInitialDriveShares != 0 && b.DriveSharingEnabled() {
diff --git a/ipn/ipnlocal/local_test.go b/ipn/ipnlocal/local_test.go
index 70cbc8991..4409befbb 100644
--- a/ipn/ipnlocal/local_test.go
+++ b/ipn/ipnlocal/local_test.go
@@ -7642,6 +7642,69 @@ func unexpectedClientVersion(t testing.TB, _ ipnauth.Actor, n *ipn.Notify) bool
 	return false
 }
 
+func TestWatchNotificationsPeerChangesImpliesInitialNetMap(t *testing.T) {
+	tests := []struct {
+		name              string
+		mask              ipn.NotifyWatchOpt
+		wantInitialNetMap bool
+	}{
+		{
+			name:              "with_notify_peer_changes",
+			mask:              ipn.NotifyPeerChanges,
+			wantInitialNetMap: true,
+		},
+		{
+			name:              "with_notify_initial_state_only",
+			mask:              ipn.NotifyInitialState,
+			wantInitialNetMap: false,
+		},
+		{
+			name:              "with_no_flags",
+			mask:              0,
+			wantInitialNetMap: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			lb := newTestLocalBackend(t)
+
+			testNetMap := &netmap.NetworkMap{
+				SelfNode: (&tailcfg.Node{
+					ID:   1,
+					Name: "self.tailscale.ts.net.",
+				}).View(),
+			}
+			lb.mu.Lock()
+			lb.setNetMapLocked(testNetMap)
+			lb.mu.Unlock()
+
+			nw := newNotificationWatcher(t, lb, ipnauth.Self)
+
+			if tt.wantInitialNetMap {
+				nw.watch(tt.mask, []wantedNotification{
+					{
+						name: "InitialNetMap",
+						cond: func(_ testing.TB, _ ipnauth.Actor, n *ipn.Notify) bool {
+							return n.NetMap != nil
+						},
+					},
+				})
+			} else {
+				nw.watch(tt.mask, nil, func(t testing.TB, _ ipnauth.Actor, n *ipn.Notify) bool {
+					if n.NetMap != nil {
+						t.Errorf("unexpected NetMap in initial notification without NotifyInitialNetMap or NotifyPeerChanges")
+						return true
+					}
+					return false
+				})
+			}
+
+			nw.check()
+		})
+	}
+}
+
 func checkError(tb testing.TB, got, want error, fatal bool) {
 	tb.Helper()
 	f := tb.Errorf