diff --git a/src/apps/epic/tests/integrated/test_views.py b/src/apps/epic/tests/integrated/test_views.py
index 8c80f35..d3db315 100644
--- a/src/apps/epic/tests/integrated/test_views.py
+++ b/src/apps/epic/tests/integrated/test_views.py
@@ -4211,6 +4211,33 @@ class PickSeaUnifiedFeltTest(TestCase):
         self.assertNotIn("sea-deck-stack--single", content)
         self.assertNotIn("sea-stacks--single", content)
 
+    def test_seed_map_btn_out_until_hand_complete(self):
+        """SEED MAP joins the hex phase stack (the post-completion cascade eases
+        it IN, mirroring CAST SKY → DRAW SEA). Pre-completion it renders --out
+        while DRAW SEA is in (user-spec 2026-06-07)."""
+        import lxml.html
+        parsed = lxml.html.fromstring(self.client.get(self.url).content)
+        [seed] = parsed.cssselect("#id_seed_map_btn")
+        self.assertIn("hex-phase-btn--out", seed.get("class", ""))
+        [sea] = parsed.cssselect("#id_pick_sea_btn")
+        self.assertNotIn("hex-phase-btn--out", sea.get("class", ""))
+
+    def test_seed_map_in_and_draw_sea_out_when_hand_complete(self):
+        """A reload of an already-complete sea lands on SEED MAP server-side:
+        SEED MAP in, DRAW SEA --out (the cascade's end-state, no animation)."""
+        card_id = TarotCard.objects.filter(deck_variant=self.earthman).first().id
+        char = Character.objects.get(seat=self.pc_seat, confirmed_at__isnull=False)
+        char.celtic_cross = {"spread": "waite-smith", "hand": [
+            {"position": p, "card_id": card_id, "reversed": False, "polarity": "gravity"}
+            for p in ["cover", "cross", "crown", "lay", "loom", "leave"]]}
+        char.save(update_fields=["celtic_cross"])
+        import lxml.html
+        parsed = lxml.html.fromstring(self.client.get(self.url).content)
+        [seed] = parsed.cssselect("#id_seed_map_btn")
+        self.assertNotIn("hex-phase-btn--out", seed.get("class", ""))
+        [sea] = parsed.cssselect("#id_pick_sea_btn")
+        self.assertIn("hex-phase-btn--out", sea.get("class", ""))
+
 
 class CarteSeatSwitchSkySeaTest(TestCase):
     """A CARTE owner (one gamer owns all 6 seats) must drive EACH seat through
diff --git a/src/static_src/scss/_sky.scss b/src/static_src/scss/_sky.scss
index 238cf5b..833883d 100644
--- a/src/static_src/scss/_sky.scss
+++ b/src/static_src/scss/_sky.scss
@@ -103,6 +103,15 @@ html.sea-open .position-strip {
     visibility: hidden;
 }
 
+// Post-completion cascade ease-out — once the 6-card spread is complete the felt
+// fades to transparent over ~0.5s (the JS _SEA_FELT_FADE timer) BEFORE sea-open
+// is removed, revealing the table-hex with a soft dissolve (mirrors the CAST SKY
+// post-save cascade's .sky-page--cascade-out).
+.sea-page.sea-page--cascade-out {
+    opacity: 0;
+    transition: opacity 0.5s ease;
+}
+
 // ── Backdrop ──────────────────────────────────────────────────────────────────
 
 .sky-backdrop {
diff --git a/src/templates/apps/gameboard/_partials/_room_hex_center.html b/src/templates/apps/gameboard/_partials/_room_hex_center.html
index 86a1f7f..e437823 100644
--- a/src/templates/apps/gameboard/_partials/_room_hex_center.html
+++ b/src/templates/apps/gameboard/_partials/_room_hex_center.html
@@ -29,14 +29,17 @@ sky_confirmed, polarity_done, user_polarity, current_slot, …).
             onclick="window.location.href='{% url 'epic:room_gate' room.id %}{% if current_slot %}?seat={{ current_slot }}{% endif %}'">GATE<br>VIEW</button>
 {% else %}
     {% if room.table_status == "SKY_SELECT" %}
-        {# Both phase btns render so the post-save cascade can cross-fade CAST   #}
-        {# SKY → DRAW SEA in place (no reload). The server sets --out on the     #}
-        {# inactive one; sky-select.js's cascade swaps them. On a confirmed      #}
-        {# reload the server lands DRAW SEA visible + CAST SKY out, same as the  #}
-        {# cascade end.                                                          #}
+        {# All three phase btns render so the cascades can cross-fade in place    #}
+        {# (no reload): CAST SKY → DRAW SEA on sky-save, then DRAW SEA → SEED MAP  #}
+        {# on the 6-card spread completing. The server sets --out on the inactive  #}
+        {# ones; the sky/sea cascades swap them. On a reload the server lands the  #}
+        {# right one visible (DRAW SEA once sky_confirmed; SEED MAP once the sea   #}
+        {# hand is complete), same as each cascade's end. SEED MAP → the Voronoi   #}
+        {# map (roadmap step 21) is a stub for now — it only needs to APPEAR here. #}
         <div class="hex-phase-stack">
             <button id="id_pick_sky_btn" class="btn btn-primary hex-phase-btn{% if sky_confirmed %} hex-phase-btn--out{% endif %}">CAST<br>SKY</button>
-            <button id="id_pick_sea_btn" class="btn btn-primary hex-phase-btn{% if not sky_confirmed %} hex-phase-btn--out{% endif %}">DRAW<br>SEA</button>
+            <button id="id_pick_sea_btn" class="btn btn-primary hex-phase-btn{% if not sky_confirmed or hand_complete %} hex-phase-btn--out{% endif %}">DRAW<br>SEA</button>
+            <button id="id_seed_map_btn" class="btn btn-primary hex-phase-btn{% if not hand_complete %} hex-phase-btn--out{% endif %}">SEED<br>MAP</button>
         </div>
     {% elif room.table_status == "SIG_SELECT" %}
         <button id="id_pick_sky_btn" class="btn btn-primary" style="display:none">CAST<br>SKY</button>
diff --git a/src/templates/apps/gameboard/_partials/_sea_overlay.html b/src/templates/apps/gameboard/_partials/_sea_overlay.html
index e06b80b..be08783 100644
--- a/src/templates/apps/gameboard/_partials/_sea_overlay.html
+++ b/src/templates/apps/gameboard/_partials/_sea_overlay.html
@@ -222,7 +222,7 @@ Each draw persists onto the seat's Character.celtic_cross via epic:sea_save.
   function _setHasDrawn(on) {
     if (delBtn) { delBtn.classList.toggle('btn-disabled', !on); delBtn.innerHTML = on ? 'DEL' : '×'; }
   }
-  function _setComplete(on) {
+  function _setComplete(on, live) {
     _locked = on;
     overlay.classList.toggle('my-sea-picker--locked', on);
     overlay.querySelectorAll('.sea-deck-stack .sea-stack-ok').forEach(function (btn) {
@@ -234,6 +234,45 @@ Each draw persists onto the seat's Character.celtic_cross via epic:sea_save.
       actionBtn.classList.toggle('btn-disabled', on);
     }
     _hideOk();
+    // Live completion (manual FLIP of the 6th card / AUTO DRAW finishing) → run
+    // the post-completion cascade. NOT on init (a reload of an already-complete
+    // sea lands on the SEED MAP hex server-side, no animation).
+    if (on && live) _startSeaCascade();
+  }
+
+  // ── Post-completion cascade (mirrors CAST SKY's _startSaveCascade) ──────────
+  // The 6-card spread completes → linger ~3s on the felt → the felt eases OUT
+  // (revealing the table-hex) → DRAW SEA gives way to SEED MAP + the sea glow
+  // fires (burger → sea_btn handoff) → +3s → SEED MAP eases IN. Same shape as
+  // the CAST SKY → sky-btn glow → DRAW SEA sequence (user-spec 2026-06-07).
+  var _SEA_CASCADE_LINGER = 3000, _SEA_FELT_FADE = 500, _SEED_DELAY = 3000;
+  var _cascadeRun = false;
+  function _startSeaCascade() {
+    if (_cascadeRun) return;
+    _cascadeRun = true;
+    setTimeout(_cascadeFeltOut, _SEA_CASCADE_LINGER);
+  }
+  function _cascadeFeltOut() {
+    page.classList.add('sea-page--cascade-out');   // CSS fades the felt out
+    setTimeout(function () {
+      document.documentElement.classList.remove('sea-open');
+      page.classList.remove('sea-page--cascade-out');
+      _restorePhaseBtns();
+      if (window.RoomViews && window.RoomViews.syncGear) window.RoomViews.syncGear();
+      // DRAW SEA is stale → ease it out; keep the sea_btn active (reopen/review)
+      // + start the sea glow handoff on the burger, concurrent w. the hex reveal.
+      var seaPhaseBtn = document.getElementById('id_pick_sea_btn');
+      if (seaPhaseBtn) seaPhaseBtn.classList.add('hex-phase-btn--out');
+      var seaBtn = document.getElementById('id_sea_btn');
+      if (seaBtn) seaBtn.classList.add('active');
+      var burgerBtn = document.getElementById('id_burger_btn');
+      if (burgerBtn) burgerBtn.classList.add('glow-handoff');
+      setTimeout(_cascadeSeedMapIn, _SEED_DELAY);
+    }, _SEA_FELT_FADE);
+  }
+  function _cascadeSeedMapIn() {
+    var seedBtn = document.getElementById('id_seed_map_btn');
+    if (seedBtn) seedBtn.classList.remove('hex-phase-btn--out');   // eases in
   }
 
   function _collectHandFromDom() {
@@ -288,7 +327,7 @@ Each draw persists onto the seat's Character.celtic_cross via epic:sea_save.
           _filled++;
           if (_filled === 1) { _lockSpread(); _setHasDrawn(true); }
           _postLock(_collectHandFromDom());
-          if (_filled >= order.length) _setComplete(true);
+          if (_filled >= order.length) _setComplete(true, true);   // live → cascade
         }
         _hideOk();
       });
@@ -320,7 +359,7 @@ Each draw persists onto the seat's Character.celtic_cross via epic:sea_save.
       _setHasDrawn(true);
       var idx = 0;
       function placeNext() {
-        if (idx >= autoEntries.length) { _setComplete(true); return; }
+        if (idx >= autoEntries.length) { _setComplete(true, true); return; }   // live → cascade
         var e = autoEntries[idx++];
         // Gameroom Sea Select always has BOTH polarity stacks (no single-stack
         // fallback — that's a my_sea monodeck concern, not here).
@@ -493,12 +532,12 @@ Each draw persists onto the seat's Character.celtic_cross via epic:sea_save.
 }());
 </script>
 
-{# ── Completion glow cue (mirrors Sky Select) — the SEA glow-machine does NOT #}
-{# fire while drawing. It starts only once ALL slots are drawn (the action btn #}
-{# flips to data-state="complete", DRAW SEA gives way to SEED MAP), then hands #}
-{# off burger → sea_btn → .sea-select so the user can review their sea. The    #}
-{# cue starts on the live completion TRANSITION (manual FLIP or AUTO DRAW), not #}
-{# on a reload of an already-complete sea. User-spec 2026-06-07.                #}
+{# ── Sea glow handoff — the SEA glow-machine does NOT fire while drawing. The  #}
+{# post-completion CASCADE (in the picker IIFE above) STARTS it on the burger   #}
+{# as the felt eases out (DRAW SEA → SEED MAP), mirroring CAST SKY's burger →   #}
+{# sky-btn cue. This IIFE only carries the handoff: burger → sea_btn →          #}
+{# .sea-select → end, so the user is led to review their sea. User-spec         #}
+{# 2026-06-07.                                                                  #}
 <script>
 (function () {
   var burgerBtn = document.getElementById('id_burger_btn');
@@ -507,16 +546,9 @@ Each draw persists onto the seat's Character.celtic_cross via epic:sea_save.
   if (!burgerBtn || !seaBtn || !modal) return;
 
   var seaSelect = modal.querySelector('.sea-select');
-  var actionBtn = document.getElementById('id_sea_action_btn');
-  if (!seaSelect || !actionBtn) return;
+  if (!seaSelect) return;
 
-  var started = false, glowDone = false;
-
-  function startGlow() {
-    if (started || glowDone) return;
-    started = true;
-    burgerBtn.classList.add('glow-handoff');
-  }
+  var glowDone = false;
   function endGlow() {
     glowDone = true;
     burgerBtn.classList.remove('glow-handoff');
@@ -524,7 +556,8 @@ Each draw persists onto the seat's Character.celtic_cross via epic:sea_save.
     seaSelect.classList.remove('glow-handoff');
   }
 
-  // Handoff on clicks: burger → sea_btn → .sea-select → end.
+  // Handoff on clicks: burger → sea_btn → .sea-select → end. (The cascade adds
+  // `glow-handoff` to the burger to begin the sequence.)
   burgerBtn.addEventListener('click', function () {
     if (glowDone || !burgerBtn.classList.contains('glow-handoff')) return;
     burgerBtn.classList.remove('glow-handoff');
@@ -539,14 +572,5 @@ Each draw persists onto the seat's Character.celtic_cross via epic:sea_save.
     if (glowDone) return;
     endGlow();
   });
-
-  // Start the cue on the live completion transition (data-state → "complete").
-  var obs = new MutationObserver(function (mutations) {
-    for (var i = 0; i < mutations.length; i++) {
-      if (mutations[i].attributeName !== 'data-state') continue;
-      if (actionBtn.dataset.state === 'complete') startGlow();
-    }
-  });
-  obs.observe(actionBtn, { attributes: true, attributeFilter: ['data-state'] });
 }());
 </script>