diff --git a/__init__.py b/__init__.py
index a8fa672..b2e1139 100644
--- a/__init__.py
+++ b/__init__.py
@@ -73,6 +73,7 @@ def chatelet_start():
         handle_room_list,
         handle_room_list_mine,
         handle_room_publish,
+        handle_room_unavailable,
         handle_room_update,
         resolve_chatelet_owner,
     )
@@ -86,6 +87,7 @@ def chatelet_start():
     # public (discovery + guest booking)
     register_rpc("chatelet_room_list", handle_room_list, AUTH_NONE)
     register_rpc("chatelet_room_get", handle_room_get, AUTH_NONE)
+    register_rpc("chatelet_room_unavailable", handle_room_unavailable, AUTH_NONE)
     register_rpc("chatelet_availability", handle_availability, AUTH_NONE)
     register_rpc("chatelet_booking_request", handle_booking_request, AUTH_NONE)
     register_rpc("chatelet_booking_get", handle_booking_get, AUTH_NONE)
diff --git a/crud.py b/crud.py
index 8ba75dd..765d703 100644
--- a/crud.py
+++ b/crud.py
@@ -12,6 +12,7 @@ from lnbits.db import Database
 from lnbits.helpers import urlsafe_short_hash
 
 from .models import (
+    OCCUPYING_STATUSES,
     Block,
     Booking,
     BookingStatus,
@@ -188,12 +189,9 @@ async def is_available(room_id: str, check_in: str, check_out: str) -> bool:
         return False
 
     for b in await get_bookings_for_room(room_id):
-        if b.status in (
-            BookingStatus.held,
-            BookingStatus.awaiting_payment,
-            BookingStatus.confirmed,
-            BookingStatus.checked_in,
-        ) and _overlaps(check_in, check_out, b.check_in, b.check_out):
+        if b.status in OCCUPYING_STATUSES and _overlaps(
+            check_in, check_out, b.check_in, b.check_out
+        ):
             return False
 
     for blk in await get_blocks_for_room(room_id):
@@ -203,6 +201,54 @@ async def is_available(room_id: str, check_in: str, check_out: str) -> bool:
     return True
 
 
+def merge_ranges(
+    ranges: list[tuple[str, str]], start: str, end: str
+) -> list[tuple[str, str]]:
+    """Clip half-open [s, e) spans to [start, end), drop empties, sort, and
+    coalesce overlapping *and adjacent* spans (a stay ending the day another
+    begins becomes one span). Pure, so the calendar shape is unit-testable
+    without a DB. Adjacent merging is deliberate: it hides where one
+    occupant's dates stop and the next's begin."""
+    clipped = sorted(
+        (max(s, start), min(e, end)) for s, e in ranges if max(s, start) < min(e, end)
+    )
+    merged: list[tuple[str, str]] = []
+    for s, e in clipped:
+        if merged and s <= merged[-1][1]:
+            merged[-1] = (merged[-1][0], max(merged[-1][1], e))
+        else:
+            merged.append((s, e))
+    return merged
+
+
+async def get_occupied_ranges(
+    room_id: str, start: str, end: str
+) -> list[tuple[str, str]]:
+    """Occupying bookings + blocks that touch [start, end), as merged spans.
+    Same statuses and the same half-open rule as `is_available`, so a night
+    the calendar shows as free is one the arbiter will accept."""
+    bookings = await db.fetchall(
+        f"""
+        SELECT * FROM chatelet.bookings
+        WHERE room_id = :rid AND check_in < :end AND check_out > :start
+          AND status IN ({", ".join(f"'{st.value}'" for st in OCCUPYING_STATUSES)})
+        """,
+        {"rid": room_id, "start": start, "end": end},
+        Booking,
+    )
+    blocks = await db.fetchall(
+        """
+        SELECT * FROM chatelet.blocks
+        WHERE room_id = :rid AND start_date < :end AND end_date > :start
+        """,
+        {"rid": room_id, "start": start, "end": end},
+        Block,
+    )
+    spans = [(b.check_in, b.check_out) for b in bookings]
+    spans += [(blk.start_date, blk.end_date) for blk in blocks]
+    return merge_ranges(spans, start, end)
+
+
 def nights_between(check_in: str, check_out: str) -> int:
     d_in = date.fromisoformat(check_in)
     d_out = date.fromisoformat(check_out)
diff --git a/docs/event-flow.md b/docs/event-flow.md
index 8fce44a..8524ab4 100644
--- a/docs/event-flow.md
+++ b/docs/event-flow.md
@@ -26,6 +26,7 @@ flow runs over relays with no HTTP:
 | `chatelet_block_create` | wallet | operator blocks a range |
 | `chatelet_room_list_mine` | account | operator's rooms across their wallets |
 | `chatelet_room_list` / `_get` | none | public discovery (active rooms, wallet id stripped) |
+| `chatelet_room_unavailable` | none | merged occupied/blocked spans over a window — the guest calendar feed (HTTP twin: `GET /api/v1/public/rooms/{id}/unavailable`) |
 | `chatelet_availability` | none | is a range free + a quote |
 | `chatelet_booking_request` | none | guest requests a stay (guest id = signed `sender_pubkey`) |
 | `chatelet_booking_get` | none | guest reads back their booking (ownership by `sender_pubkey`) |
diff --git a/models.py b/models.py
index 77d4537..346b4e0 100644
--- a/models.py
+++ b/models.py
@@ -231,6 +231,27 @@ class AvailabilityQuery(BaseModel):
     check_out: str  # YYYY-MM-DD exclusive
 
 
+class DateRange(BaseModel):
+    """Half-open [start, end) span of nights, YYYY-MM-DD. `end` is the morning
+    the room frees up — a guest may check in on that day."""
+
+    start: str
+    end: str
+
+
+class UnavailableRanges(BaseModel):
+    """Everything a guest calendar needs to grey out nights for one room
+    over a window: bookings that still occupy the room (incl. live unpaid
+    holds, so this always agrees with `POST /availability`) and manual
+    blocks, merged into indistinguishable date spans — a guest can't tell a
+    block from another guest's stay."""
+
+    room_id: str
+    start: str
+    end: str
+    ranges: list[DateRange] = Field(default_factory=list)
+
+
 class AvailabilityResult(BaseModel):
     room_id: str
     check_in: str
diff --git a/services.py b/services.py
index 7607fa8..ea6e4f9 100644
--- a/services.py
+++ b/services.py
@@ -14,7 +14,7 @@ backend failure and surfaces as a generic error over RPC (logged server-side).
 
 import asyncio
 from collections import defaultdict
-from datetime import datetime, timedelta, timezone
+from datetime import date, datetime, timedelta, timezone
 
 from lnbits.core.services import create_invoice
 from lnbits.exceptions import InvoiceError
@@ -28,7 +28,9 @@ from .models import (
     BookingQuote,
     BookingRequestData,
     BookingStatus,
+    DateRange,
     RoomStatus,
+    UnavailableRanges,
 )
 
 # Per-room lock serializing the availability read + the `held` write, so two
@@ -59,6 +61,46 @@ async def to_sats(amount: float, currency: str) -> int:
     return await fiat_amount_as_satoshis(amount, currency)
 
 
+# A guest calendar asks for a year by default; cap the window so a bad client
+# can't make us scan and ship an unbounded span.
+DEFAULT_CALENDAR_DAYS = 365
+MAX_CALENDAR_DAYS = 400
+
+
+async def get_unavailable_ranges(
+    room_id: str, start: str | None = None, end: str | None = None
+) -> UnavailableRanges:
+    """Occupied/blocked nights for one active room over [start, end).
+    Defaults to today → +365 days (UTC dates)."""
+    room = await crud.get_room(room_id)
+    if not room or room.status != RoomStatus.active:
+        raise NotFound("Room not available")
+    try:
+        d_start = (
+            date.fromisoformat(start) if start else datetime.now(timezone.utc).date()
+        )
+        d_end = (
+            date.fromisoformat(end)
+            if end
+            else d_start + timedelta(days=DEFAULT_CALENDAR_DAYS)
+        )
+    except ValueError as exc:
+        raise ValueError("Dates must be YYYY-MM-DD") from exc
+    if d_end <= d_start:
+        raise ValueError("end must be after start")
+    if (d_end - d_start).days > MAX_CALENDAR_DAYS:
+        raise ValueError(f"Window may span at most {MAX_CALENDAR_DAYS} days")
+    spans = await crud.get_occupied_ranges(
+        room_id, d_start.isoformat(), d_end.isoformat()
+    )
+    return UnavailableRanges(
+        room_id=room_id,
+        start=d_start.isoformat(),
+        end=d_end.isoformat(),
+        ranges=[DateRange(start=s, end=e) for s, e in spans],
+    )
+
+
 async def get_availability(
     room_id: str, check_in: str, check_out: str
 ) -> AvailabilityResult:
diff --git a/tests/test_unavailable_ranges.py b/tests/test_unavailable_ranges.py
new file mode 100644
index 0000000..c5d7203
--- /dev/null
+++ b/tests/test_unavailable_ranges.py
@@ -0,0 +1,133 @@
+"""Guest calendar feed: merged, anonymous occupied spans for one room."""
+
+import asyncio
+from datetime import datetime, timedelta, timezone
+
+import pytest
+from fastapi import HTTPException
+
+from .. import crud, services, transport_rpcs, views_api
+from ..models import RoomStatus
+from .conftest import make_room
+
+# --- merge_ranges (pure) ---------------------------------------------------
+
+
+def test_merge_sorts_and_coalesces_overlap_and_adjacency():
+    spans = [
+        ("2026-10-10", "2026-10-12"),
+        ("2026-10-01", "2026-10-04"),
+        ("2026-10-04", "2026-10-06"),  # adjacent to the first: one span
+        ("2026-10-11", "2026-10-15"),  # overlaps the 10-12 stay
+    ]
+    out = crud.merge_ranges(spans, "2026-09-01", "2027-09-01")
+    assert out == [("2026-10-01", "2026-10-06"), ("2026-10-10", "2026-10-15")]
+
+
+def test_merge_clips_to_window_and_drops_outside():
+    spans = [
+        ("2026-08-20", "2026-09-05"),  # straddles the window start
+        ("2026-12-28", "2027-01-10"),  # straddles the window end
+        ("2026-07-01", "2026-07-03"),  # entirely before
+        ("2027-02-01", "2027-02-03"),  # entirely after
+    ]
+    out = crud.merge_ranges(spans, "2026-09-01", "2027-01-01")
+    assert out == [("2026-09-01", "2026-09-05"), ("2026-12-28", "2027-01-01")]
+
+
+def test_merge_empty():
+    assert crud.merge_ranges([], "2026-09-01", "2027-01-01") == []
+
+
+# --- services.get_unavailable_ranges ----------------------------------------
+
+
+def _patch(monkeypatch, room, spans):
+    seen: dict = {}
+
+    async def gr(_):
+        return room
+
+    async def occupied(room_id, start, end):
+        seen.update(room_id=room_id, start=start, end=end)
+        return spans
+
+    monkeypatch.setattr(crud, "get_room", gr)
+    monkeypatch.setattr(crud, "get_occupied_ranges", occupied)
+    return seen
+
+
+def test_defaults_to_today_plus_365(monkeypatch):
+    seen = _patch(monkeypatch, make_room("a", status=RoomStatus.active), [])
+    out = asyncio.run(services.get_unavailable_ranges("a"))
+    today = datetime.now(timezone.utc).date()
+    assert out.start == today.isoformat()
+    assert out.end == (today + timedelta(days=365)).isoformat()
+    assert (seen["start"], seen["end"]) == (out.start, out.end)
+    assert out.ranges == []
+
+
+def test_explicit_window_and_shape(monkeypatch):
+    _patch(
+        monkeypatch,
+        make_room("a", status=RoomStatus.active),
+        [("2026-10-05", "2026-10-07")],
+    )
+    out = asyncio.run(services.get_unavailable_ranges("a", "2026-10-01", "2026-11-01"))
+    assert (out.room_id, out.start, out.end) == ("a", "2026-10-01", "2026-11-01")
+    assert [(r.start, r.end) for r in out.ranges] == [("2026-10-05", "2026-10-07")]
+
+
+@pytest.mark.parametrize(
+    ("start", "end"),
+    [
+        ("2026-10-10", "2026-10-10"),  # empty window
+        ("2026-10-10", "2026-10-01"),  # reversed
+        ("2026-01-01", "2027-03-01"),  # > 400 days
+        ("not-a-date", None),
+    ],
+)
+def test_window_validation(monkeypatch, start, end):
+    _patch(monkeypatch, make_room("a", status=RoomStatus.active), [])
+    with pytest.raises(ValueError):
+        asyncio.run(services.get_unavailable_ranges("a", start, end))
+
+
+def test_inactive_room_is_not_found(monkeypatch):
+    _patch(monkeypatch, make_room("a", status=RoomStatus.inactive), [])
+    with pytest.raises(services.NotFound):
+        asyncio.run(services.get_unavailable_ranges("a"))
+
+
+# --- both doors -------------------------------------------------------------
+
+
+def test_http_and_rpc_doors_agree(monkeypatch):
+    _patch(
+        monkeypatch,
+        make_room("a", status=RoomStatus.active),
+        [("2026-10-05", "2026-10-07")],
+    )
+    http = asyncio.run(
+        views_api.api_public_room_unavailable("a", "2026-10-01", "2026-11-01")
+    )
+    rpc = asyncio.run(
+        transport_rpcs.handle_room_unavailable(
+            None,
+            transport_rpcs.NostrRpcRequest(
+                rpc_name="chatelet_room_unavailable",
+                request_id="req-1",
+                body={"room_id": "a", "start": "2026-10-01", "end": "2026-11-01"},
+                sender_pubkey="ab" * 32,
+            ),
+        )
+    )
+    assert rpc == http.dict()
+    assert rpc["ranges"] == [{"start": "2026-10-05", "end": "2026-10-07"}]
+
+
+def test_http_maps_errors(monkeypatch):
+    _patch(monkeypatch, make_room("a", status=RoomStatus.inactive), [])
+    with pytest.raises(HTTPException) as e:
+        asyncio.run(views_api.api_public_room_unavailable("a", None, None))
+    assert e.value.status_code == 404
diff --git a/transport_rpcs.py b/transport_rpcs.py
index d3e5cc3..71ee687 100644
--- a/transport_rpcs.py
+++ b/transport_rpcs.py
@@ -115,6 +115,16 @@ async def handle_room_get(auth: None, request: NostrRpcRequest) -> dict:
     return _public_room(room)
 
 
+async def handle_room_unavailable(auth: None, request: NostrRpcRequest) -> dict:
+    """Merged occupied/blocked spans for one room — the calendar feed.
+    Body: {room_id, start?, end?} (YYYY-MM-DD, end exclusive)."""
+    body = request.body or {}
+    result = await services.get_unavailable_ranges(
+        _require(body, "room_id"), body.get("start"), body.get("end")
+    )
+    return _to_dict(result)
+
+
 async def handle_availability(auth: None, request: NostrRpcRequest) -> dict:
     body = request.body or {}
     result = await services.get_availability(
diff --git a/views_api.py b/views_api.py
index cc45519..2e306fd 100644
--- a/views_api.py
+++ b/views_api.py
@@ -7,7 +7,7 @@ endpoints (room/block CRUD, settings) are HTTP-only and back the admin UI;
 the guest-facing surface (availability, booking) is what also rides the RPC.
 """
 
-from fastapi import APIRouter, Depends, HTTPException
+from fastapi import APIRouter, Depends, HTTPException, Query
 from lnbits.core.models import WalletTypeInfo
 from lnbits.decorators import require_admin_key, require_invoice_key
 
@@ -24,6 +24,7 @@ from .models import (
     CreateRoomData,
     Room,
     RoomStatus,
+    UnavailableRanges,
     public_booking_dict,
     public_room_dict,
 )
@@ -212,6 +213,20 @@ async def api_public_room(room_id: str) -> dict:
     return public_room_dict(room)
 
 
+@chatelet_api_router.get("/api/v1/public/rooms/{room_id}/unavailable")
+async def api_public_room_unavailable(
+    room_id: str,
+    start: str | None = Query(None, description="YYYY-MM-DD, default today"),
+    end: str | None = Query(None, description="YYYY-MM-DD exclusive, default +365d"),
+) -> UnavailableRanges:
+    """Nights a guest cannot book, merged and anonymous — what a calendar
+    greys out. Keyless, like the room read it hangs off."""
+    try:
+        return await services.get_unavailable_ranges(room_id, start, end)
+    except ValueError as exc:
+        raise _to_http(exc) from exc
+
+
 # --- availability (public read) --------------------------------------------