diff --git a/apps/web/src/__tests__/Appointments.test.tsx b/apps/web/src/__tests__/Appointments.test.tsx
index 344ea97..ade71a7 100644
--- a/apps/web/src/__tests__/Appointments.test.tsx
+++ b/apps/web/src/__tests__/Appointments.test.tsx
@@ -28,15 +28,6 @@ const PAST_APPT: Appointment = {
   status: "completed",
 };
 
-const mockSessionStorage = {
-  getItem: vi.fn(),
-  setItem: vi.fn(),
-  removeItem: vi.fn(),
-  clear: vi.fn(),
-};
-
-vi.stubGlobal("sessionStorage", mockSessionStorage);
-
 describe("parseTimeTo24Hour", () => {
   it("converts AM times correctly", () => {
     expect(parseTimeTo24Hour("9:00 AM")).toBe("09:00:00");
@@ -73,17 +64,16 @@ describe("isUpcoming", () => {
 describe("CustomerNotesSection", () => {
   beforeEach(() => {
     vi.clearAllMocks();
-    mockSessionStorage.getItem.mockReturnValue("test-session-id");
     global.fetch = vi.fn();
   });
 
   it("renders textarea with existing notes", () => {
-    render(<CustomerNotesSection appointment={{ ...UPCOMING_APPT, customerNotes: "Test note" }} />);
+    render(<CustomerNotesSection appointment={{ ...UPCOMING_APPT, customerNotes: "Test note" }} sessionId="test-session-id" />);
     expect(screen.getByRole("textbox")).toHaveValue("Test note");
   });
 
   it("renders Save Notes button", () => {
-    render(<CustomerNotesSection appointment={UPCOMING_APPT} />);
+    render(<CustomerNotesSection appointment={UPCOMING_APPT} sessionId="test-session-id" />);
     expect(screen.getByRole("button", { name: /Save Notes/i })).toBeInTheDocument();
   });
 
@@ -93,7 +83,7 @@ describe("CustomerNotesSection", () => {
       json: async () => ({ id: "appt-1", customerNotes: "Updated", updatedAt: new Date().toISOString() }),
     } as Response);
 
-    render(<CustomerNotesSection appointment={UPCOMING_APPT} />);
+    render(<CustomerNotesSection appointment={UPCOMING_APPT} sessionId="test-session-id" />);
     fireEvent.change(screen.getByRole("textbox"), { target: { value: "New note" } });
     fireEvent.click(screen.getByRole("button", { name: /Save Notes/i }));
 
@@ -109,6 +99,28 @@ describe("CustomerNotesSection", () => {
     });
   });
 
+  it("does not send X-Impersonation-Session-Id header when sessionId is null", async () => {
+    vi.mocked(global.fetch).mockResolvedValue({
+      ok: true,
+      json: async () => ({ id: "appt-1", customerNotes: "Updated", updatedAt: new Date().toISOString() }),
+    } as Response);
+
+    render(<CustomerNotesSection appointment={UPCOMING_APPT} sessionId={null} />);
+    fireEvent.change(screen.getByRole("textbox"), { target: { value: "New note" } });
+    fireEvent.click(screen.getByRole("button", { name: /Save Notes/i }));
+
+    await waitFor(() => {
+      expect(global.fetch).toHaveBeenCalledWith(
+        "/api/portal/appointments/appt-1/notes",
+        expect.objectContaining({
+          headers: expect.not.objectContaining({
+            "X-Impersonation-Session-Id": expect.anything(),
+          }),
+        })
+      );
+    });
+  });
+
   it("shows error message when save fails", async () => {
     vi.mocked(global.fetch).mockResolvedValue({
       ok: false,
@@ -116,7 +128,7 @@ describe("CustomerNotesSection", () => {
       json: async () => ({ error: "Unauthorized" }),
     } as Response);
 
-    render(<CustomerNotesSection appointment={UPCOMING_APPT} />);
+    render(<CustomerNotesSection appointment={UPCOMING_APPT} sessionId="test-session-id" />);
     fireEvent.change(screen.getByRole("textbox"), { target: { value: "New note" } });
     fireEvent.click(screen.getByRole("button", { name: /Save Notes/i }));
 
@@ -131,7 +143,7 @@ describe("CustomerNotesSection", () => {
       json: async () => ({ id: "appt-1", customerNotes: "Saved", updatedAt: new Date().toISOString() }),
     } as Response);
 
-    render(<CustomerNotesSection appointment={UPCOMING_APPT} />);
+    render(<CustomerNotesSection appointment={UPCOMING_APPT} sessionId="test-session-id" />);
     fireEvent.change(screen.getByRole("textbox"), { target: { value: "Saved note" } });
     fireEvent.click(screen.getByRole("button", { name: /Save Notes/i }));
 
@@ -141,12 +153,12 @@ describe("CustomerNotesSection", () => {
   });
 
   it("disables button when notes unchanged", () => {
-    render(<CustomerNotesSection appointment={{ ...UPCOMING_APPT, customerNotes: "Existing" }} />);
+    render(<CustomerNotesSection appointment={{ ...UPCOMING_APPT, customerNotes: "Existing" }} sessionId="test-session-id" />);
     expect(screen.getByRole("button", { name: /Save Notes/i })).toBeDisabled();
   });
 
   it("enforces 500 character limit", () => {
-    render(<CustomerNotesSection appointment={UPCOMING_APPT} />);
+    render(<CustomerNotesSection appointment={UPCOMING_APPT} sessionId="test-session-id" />);
     const textarea = screen.getByRole("textbox");
     const longText = "a".repeat(600);
     fireEvent.change(textarea, { target: { value: longText } });
@@ -154,12 +166,12 @@ describe("CustomerNotesSection", () => {
   });
 
   it("displays character count", () => {
-    render(<CustomerNotesSection appointment={UPCOMING_APPT} />);
+    render(<CustomerNotesSection appointment={UPCOMING_APPT} sessionId="test-session-id" />);
     expect(screen.getByText(/0\/500/)).toBeInTheDocument();
   });
 
   it("shows exceeded character count in red when limit exceeded", () => {
-    render(<CustomerNotesSection appointment={UPCOMING_APPT} />);
+    render(<CustomerNotesSection appointment={UPCOMING_APPT} sessionId="test-session-id" />);
     const textarea = screen.getByRole("textbox");
     // Type characters one by one to exceed limit
     const longText = "a".repeat(501);
@@ -171,12 +183,12 @@ describe("CustomerNotesSection", () => {
   });
 
   it("does not render save button for completed appointments", () => {
-    render(<CustomerNotesSection appointment={{ ...UPCOMING_APPT, status: "completed" }} />);
+    render(<CustomerNotesSection appointment={{ ...UPCOMING_APPT, status: "completed" }} sessionId="test-session-id" />);
     expect(screen.queryByRole("button", { name: /Save Notes/i })).not.toBeInTheDocument();
   });
 
   it("does not render save button for cancelled appointments", () => {
-    render(<CustomerNotesSection appointment={{ ...UPCOMING_APPT, status: "cancelled" }} />);
+    render(<CustomerNotesSection appointment={{ ...UPCOMING_APPT, status: "cancelled" }} sessionId="test-session-id" />);
     expect(screen.queryByRole("button", { name: /Save Notes/i })).not.toBeInTheDocument();
   });
 });
\ No newline at end of file
diff --git a/apps/web/src/portal/CustomerPortal.tsx b/apps/web/src/portal/CustomerPortal.tsx
index b74e297..65a17e3 100644
--- a/apps/web/src/portal/CustomerPortal.tsx
+++ b/apps/web/src/portal/CustomerPortal.tsx
@@ -114,7 +114,7 @@ export function CustomerPortal() {
       case "dashboard":
         return <Dashboard onNavigate={handleNavClick} readOnly={!!isReadOnly} />;
       case "appointments":
-        return <AppointmentsSection readOnly={!!isReadOnly} />;
+        return <AppointmentsSection readOnly={!!isReadOnly} sessionId={session?.id ?? null} />;
       case "pets":
         return <PetProfiles readOnly={!!isReadOnly} />;
       case "reports":
diff --git a/apps/web/src/portal/sections/Appointments.tsx b/apps/web/src/portal/sections/Appointments.tsx
index a937e08..bd38475 100644
--- a/apps/web/src/portal/sections/Appointments.tsx
+++ b/apps/web/src/portal/sections/Appointments.tsx
@@ -7,6 +7,7 @@ const MAX_CUSTOMER_NOTES = 500;
 
 interface Props {
   readOnly: boolean;
+  sessionId?: string | null;
 }
 
 export function formatDate(dateStr: string): string {
@@ -40,7 +41,7 @@ const STATUS_COLORS: Record<string, string> = {
   cancelled: "bg-red-100 text-red-600",
 };
 
-export function AppointmentsSection({ readOnly }: Props) {
+export function AppointmentsSection({ readOnly, sessionId }: Props) {
   const [showBooking, setShowBooking] = useState(false);
   const [expandedId, setExpandedId] = useState<string | null>(null);
   const [tab, setTab] = useState<"upcoming" | "past">("upcoming");
@@ -82,6 +83,7 @@ export function AppointmentsSection({ readOnly }: Props) {
               expanded={expandedId === appt.id}
               onToggle={() => setExpandedId(expandedId === appt.id ? null : appt.id)}
               readOnly={readOnly}
+              sessionId={sessionId}
             />
           ))}
           {UPCOMING_APPOINTMENTS.length === 0 && (
@@ -99,6 +101,7 @@ export function AppointmentsSection({ readOnly }: Props) {
               expanded={expandedId === appt.id}
               onToggle={() => setExpandedId(expandedId === appt.id ? null : appt.id)}
               readOnly={readOnly}
+              sessionId={sessionId}
             />
           ))}
         </div>
@@ -115,9 +118,9 @@ export function AppointmentsSection({ readOnly }: Props) {
 }
 
 function AppointmentCard({
-  appointment: appt, expanded, onToggle, readOnly,
+  appointment: appt, expanded, onToggle, readOnly, sessionId,
 }: {
-  appointment: Appointment; expanded: boolean; onToggle: () => void; readOnly: boolean;
+  appointment: Appointment; expanded: boolean; onToggle: () => void; readOnly: boolean; sessionId?: string | null;
 }) {
   return (
     <div className="bg-white rounded-xl border border-stone-200 shadow-sm overflow-hidden">
@@ -160,7 +163,7 @@ function AppointmentCard({
             <p className="text-sm text-stone-600 bg-stone-50 rounded-lg px-3 py-2 mb-3">{appt.notes}</p>
           )}
           {isUpcoming(appt) && !readOnly && (
-            <CustomerNotesSection appointment={appt} />
+            <CustomerNotesSection appointment={appt} sessionId={sessionId} />
           )}
           {appt.status !== "completed" && appt.status !== "cancelled" && !readOnly && (
             <div className="flex gap-2 mt-3">
@@ -185,7 +188,7 @@ function AppointmentCard({
   );
 }
 
-export function CustomerNotesSection({ appointment: appt }: { appointment: Appointment }) {
+export function CustomerNotesSection({ appointment: appt, sessionId }: { appointment: Appointment; sessionId?: string | null }) {
   const [notes, setNotes] = useState(appt.customerNotes || "");
   const [saving, setSaving] = useState(false);
   const [saved, setSaved] = useState(false);
@@ -193,16 +196,11 @@ export function CustomerNotesSection({ appointment: appt }: { appointment: Appoi
 
   const isDisabled = appt.status === "completed" || appt.status === "cancelled";
 
-  function getSessionId(): string | null {
-    return sessionStorage.getItem("impersonationSessionId");
-  }
-
   async function handleSave() {
     setSaving(true);
     setError(null);
     setSaved(false);
     try {
-      const sessionId = getSessionId();
       const headers: Record<string, string> = { "Content-Type": "application/json" };
       if (sessionId) {
         headers["X-Impersonation-Session-Id"] = sessionId;