diff --git a/apps/web/src/pages/Appointments.tsx b/apps/web/src/pages/Appointments.tsx
index 505953c..4d64b1b 100644
--- a/apps/web/src/pages/Appointments.tsx
+++ b/apps/web/src/pages/Appointments.tsx
@@ -707,6 +707,7 @@ function AppointmentDetail({
                 ? `✗ Customer cancelled${appt.cancelledAt ? ` (${new Date(appt.cancelledAt).toLocaleString()})` : ""}`
                 : "Pending"],
             ["Notes", appt.notes ?? "—"],
+            ...(appt.customerNotes ? [["Customer Notes", appt.customerNotes] as [string, string]] : []),
             ...(appt.seriesId
               ? [["Series slot", `#${(appt.seriesIndex ?? 0) + 1}`] as [string, string]]
               : []),
diff --git a/apps/web/src/portal/mockData.ts b/apps/web/src/portal/mockData.ts
index ed52a0e..190b41a 100644
--- a/apps/web/src/portal/mockData.ts
+++ b/apps/web/src/portal/mockData.ts
@@ -42,6 +42,7 @@ export interface Appointment {
   price: number;
   status: "confirmed" | "pending" | "waitlisted" | "completed" | "cancelled";
   notes: string;
+  customerNotes: string;
   reportCardId?: string;
 }
 
@@ -177,18 +178,21 @@ export const UPCOMING_APPOINTMENTS: Appointment[] = [
     services: ["Full Groom"], addOns: ["De-shedding Treatment"],
     date: "2026-03-21", time: "10:00 AM", duration: 120, price: 145,
     status: "confirmed", notes: "Spring shed is heavy — extra undercoat work needed",
+    customerNotes: "",
   },
   {
     id: "a2", petId: "p2", petName: "Mochi", groomerId: "g3", groomerName: "Morgan",
     services: ["Full Groom"], addOns: ["Teeth Brushing"],
     date: "2026-03-25", time: "2:00 PM", duration: 100, price: 90,
     status: "confirmed", notes: "First visit with Morgan — patient with anxious pets",
+    customerNotes: "",
   },
   {
     id: "a3", petId: "p1", petName: "Biscuit", groomerId: "g1", groomerName: "Jamie",
     services: ["Bath & Brush"], addOns: [],
     date: "2026-04-18", time: "11:00 AM", duration: 45, price: 55,
     status: "pending", notes: "",
+    customerNotes: "",
   },
 ];
 
@@ -198,48 +202,56 @@ export const PAST_APPOINTMENTS: Appointment[] = [
     services: ["Full Groom"], addOns: ["De-shedding Treatment", "Blueberry Facial"],
     date: "2026-02-15", time: "10:00 AM", duration: 130, price: 160,
     status: "completed", notes: "", reportCardId: "rc1",
+    customerNotes: "",
   },
   {
     id: "pa2", petId: "p2", petName: "Mochi", groomerId: "g2", groomerName: "Alex",
     services: ["Full Groom"], addOns: ["Teeth Brushing"],
     date: "2026-02-20", time: "1:00 PM", duration: 100, price: 88,
     status: "completed", notes: "", reportCardId: "rc2",
+    customerNotes: "",
   },
   {
     id: "pa3", petId: "p1", petName: "Biscuit", groomerId: "g1", groomerName: "Jamie",
     services: ["Bath & Brush"], addOns: [],
     date: "2026-01-18", time: "9:00 AM", duration: 45, price: 55,
     status: "completed", notes: "",
+    customerNotes: "",
   },
   {
     id: "pa4", petId: "p2", petName: "Mochi", groomerId: "g2", groomerName: "Alex",
     services: ["Puppy's First Groom"], addOns: [],
     date: "2026-01-10", time: "3:00 PM", duration: 60, price: 62,
     status: "completed", notes: "",
+    customerNotes: "",
   },
   {
     id: "pa5", petId: "p1", petName: "Biscuit", groomerId: "g1", groomerName: "Jamie",
     services: ["Full Groom"], addOns: ["Nail Grinding"],
     date: "2025-12-20", time: "10:00 AM", duration: 105, price: 132,
     status: "completed", notes: "Holiday groom",
+    customerNotes: "",
   },
   {
     id: "pa6", petId: "p1", petName: "Biscuit", groomerId: "g2", groomerName: "Alex",
     services: ["Full Groom"], addOns: [],
     date: "2025-11-15", time: "11:00 AM", duration: 90, price: 110,
     status: "completed", notes: "",
+    customerNotes: "",
   },
   {
     id: "pa7", petId: "p2", petName: "Mochi", groomerId: "g3", groomerName: "Morgan",
     services: ["Bath & Brush"], addOns: [],
     date: "2025-11-08", time: "2:00 PM", duration: 45, price: 48,
     status: "completed", notes: "",
+    customerNotes: "",
   },
   {
     id: "pa8", petId: "p1", petName: "Biscuit", groomerId: "g1", groomerName: "Jamie",
     services: ["Bath & Brush"], addOns: ["De-shedding Treatment"],
     date: "2025-10-12", time: "10:00 AM", duration: 75, price: 85,
     status: "completed", notes: "",
+    customerNotes: "",
   },
 ];
 
diff --git a/apps/web/src/portal/sections/Appointments.tsx b/apps/web/src/portal/sections/Appointments.tsx
index fdb9281..2b96952 100644
--- a/apps/web/src/portal/sections/Appointments.tsx
+++ b/apps/web/src/portal/sections/Appointments.tsx
@@ -1,8 +1,10 @@
 import { useState } from "react";
-import { Calendar, Clock, Plus, ChevronRight, ChevronDown, Search, Repeat } from "lucide-react";
+import { Calendar, Clock, Plus, ChevronRight, ChevronDown, Search, Repeat, Loader2 } from "lucide-react";
 import { UPCOMING_APPOINTMENTS, PAST_APPOINTMENTS, PETS, SERVICES, GROOMERS } from "../mockData.js";
 import type { Appointment, Pet, Service, Groomer } from "../mockData.js";
 
+const MAX_CUSTOMER_NOTES = 500;
+
 interface Props {
   readOnly: boolean;
 }
@@ -11,6 +13,12 @@ function formatDate(dateStr: string): string {
   return new Date(dateStr).toLocaleDateString("en-US", { weekday: "short", month: "short", day: "numeric", year: "numeric" });
 }
 
+function isUpcoming(appt: Appointment): boolean {
+  const now = new Date();
+  const apptDate = new Date(`${appt.date}T${appt.time}`);
+  return apptDate > now && appt.status !== "cancelled" && appt.status !== "completed";
+}
+
 const STATUS_COLORS: Record<string, string> = {
   confirmed: "bg-green-100 text-green-700",
   pending: "bg-amber-100 text-amber-700",
@@ -138,8 +146,11 @@ function AppointmentCard({
           {appt.notes && (
             <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} />
+          )}
           {appt.status !== "completed" && appt.status !== "cancelled" && !readOnly && (
-            <div className="flex gap-2">
+            <div className="flex gap-2 mt-3">
               <button className="text-xs px-3 py-1.5 border border-stone-200 rounded-lg text-stone-600 hover:bg-stone-50">
                 Reschedule
               </button>
@@ -161,6 +172,69 @@ function AppointmentCard({
   );
 }
 
+function CustomerNotesSection({ appointment: appt }: { appointment: Appointment }) {
+  const [notes, setNotes] = useState(appt.customerNotes || "");
+  const [saving, setSaving] = useState(false);
+  const [saved, setSaved] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  const isDisabled = appt.status === "completed" || appt.status === "cancelled";
+
+  async function handleSave() {
+    setSaving(true);
+    setError(null);
+    setSaved(false);
+    try {
+      const res = await fetch(`/api/portal/appointments/${appt.id}/notes`, {
+        method: "PATCH",
+        headers: { "Content-Type": "application/json" },
+        body: JSON.stringify({ customerNotes: notes }),
+      });
+      if (!res.ok) {
+        const err = await res.json().catch(() => ({ error: "Failed to save" }));
+        throw new Error(err.error || `HTTP ${res.status}`);
+      }
+      setSaved(true);
+      setTimeout(() => setSaved(false), 2000);
+    } catch (e) {
+      setError(e instanceof Error ? e.message : "Failed to save");
+    } finally {
+      setSaving(false);
+    }
+  }
+
+  return (
+    <div className="mt-3 p-3 bg-stone-50 rounded-lg">
+      <div className="flex items-center justify-between mb-1.5">
+        <label className="text-xs font-medium text-stone-600">Notes for your groomer</label>
+        <span className={`text-xs ${notes.length > MAX_CUSTOMER_NOTES ? "text-red-500" : "text-stone-400"}`}>
+          {notes.length}/{MAX_CUSTOMER_NOTES}
+        </span>
+      </div>
+      <textarea
+        value={notes}
+        onChange={e => setNotes(e.target.value.slice(0, MAX_CUSTOMER_NOTES))}
+        disabled={isDisabled}
+        className="w-full text-sm border border-stone-200 rounded-lg px-3 py-2 resize-none focus:outline-none focus:ring-2 focus:ring-(--color-accent) disabled:bg-stone-100 disabled:text-stone-400"
+        rows={3}
+        placeholder="Any special requests or notes for this appointment..."
+      />
+      {error && <p className="text-xs text-red-500 mt-1">{error}</p>}
+      {saved && <p className="text-xs text-green-600 mt-1">Saved!</p>}
+      {!isDisabled && (
+        <button
+          onClick={handleSave}
+          disabled={saving || notes === appt.customerNotes}
+          className="mt-2 flex items-center gap-1.5 text-xs px-3 py-1.5 bg-(--color-accent) text-white rounded-lg font-medium hover:bg-(--color-accent-hover) disabled:opacity-50 disabled:cursor-not-allowed"
+        >
+          {saving && <Loader2 size={12} className="animate-spin" />}
+          {saving ? "Saving..." : "Save Notes"}
+        </button>
+      )}
+    </div>
+  );
+}
+
 function BookingFlow({ onClose, readOnly }: { onClose: () => void; readOnly: boolean }) {
   const [step, setStep] = useState(1);
   const [selectedPet, setSelectedPet] = useState<Pet | null>(null);
diff --git a/packages/types/src/index.ts b/packages/types/src/index.ts
index b794c93..b019921 100644
--- a/packages/types/src/index.ts
+++ b/packages/types/src/index.ts
@@ -110,6 +110,7 @@ export interface Appointment {
   confirmedAt: string | null;
   cancelledAt: string | null;
   confirmationToken: string | null;
+  customerNotes: string | null;
   createdAt: string;
   updatedAt: string;
 }