diff --git a/apps/web/src/routes/(app)/collective/manage/+page.svelte b/apps/web/src/routes/(app)/collective/manage/+page.svelte
index fc66cb6..b2f7012 100644
--- a/apps/web/src/routes/(app)/collective/manage/+page.svelte
+++ b/apps/web/src/routes/(app)/collective/manage/+page.svelte
@@ -1,5 +1,6 @@
 <script lang="ts">
 	import { onMount } from 'svelte';
+	import { goto } from '$app/navigation';
 	import { getSupabase } from '$lib/supabase';
 	import { currentUser } from '$lib/stores/auth';
 	import { currentCollective, collectiveMembers, userCollectives } from '$lib/stores/collective';
@@ -212,6 +213,92 @@
 		currentCollective.set(c);
 		userCollectives.update((list) => list.map((it) => (it.id === c.id ? c : it)));
 	}
+
+	// ── Fase 10.3: dissolve collective (CU-H08) ─────────────────────────────
+	let dissolveOpen = $state(false);
+	let dissolveConfirmInput = $state('');
+	let dissolveError = $state<string | null>(null);
+	let dissolveInFlight = $state(false);
+	let listsCount = $state(0);
+	let tasksCount = $state(0);
+	let notesCount = $state(0);
+
+	const dissolveConfirmReady = $derived(
+		!!$currentCollective && dissolveConfirmInput === $currentCollective.name
+	);
+
+	async function openDissolve() {
+		if (!$currentCollective || !isAdmin) return;
+		dissolveOpen = true;
+		dissolveConfirmInput = '';
+		dissolveError = null;
+		// Best-effort counts; failures fall back to 0.
+		const supabase = getSupabase();
+		const [l, t, n] = await Promise.all([
+			supabase
+				.from('shopping_lists')
+				.select('id', { head: true, count: 'exact' })
+				.eq('collective_id', $currentCollective.id),
+			supabase
+				.from('tasks')
+				.select('id', { head: true, count: 'exact' })
+				.in(
+					'list_id',
+					(
+						await supabase
+							.from('task_lists')
+							.select('id')
+							.eq('collective_id', $currentCollective.id)
+					).data?.map((r) => r.id) ?? []
+				),
+			supabase
+				.from('notes')
+				.select('id', { head: true, count: 'exact' })
+				.eq('collective_id', $currentCollective.id)
+		]);
+		listsCount = l.count ?? 0;
+		tasksCount = t.count ?? 0;
+		notesCount = n.count ?? 0;
+	}
+
+	function closeDissolve() {
+		dissolveOpen = false;
+		dissolveConfirmInput = '';
+		dissolveError = null;
+	}
+
+	async function confirmDissolve() {
+		if (!$currentCollective || !dissolveConfirmReady || dissolveInFlight) return;
+		const target = $currentCollective;
+		dissolveInFlight = true;
+		dissolveError = null;
+
+		const { error: rpcErr } = await getSupabase().rpc('dissolve_collective', {
+			p_collective_id: target.id
+		});
+		if (rpcErr) {
+			dissolveInFlight = false;
+			dissolveError = rpcErr.message;
+			return;
+		}
+
+		// Update local stores. Pick the next collective or redirect to onboarding.
+		const remaining = $userCollectives.filter((c) => c.id !== target.id);
+		userCollectives.set(remaining);
+		dissolveOpen = false;
+		dissolveInFlight = false;
+
+		if (remaining.length > 0) {
+			const next = remaining[0];
+			currentCollective.set(next);
+			localStorage.setItem('activeCollectiveId', next.id);
+			await goto('/lists');
+		} else {
+			currentCollective.set(null);
+			localStorage.removeItem('activeCollectiveId');
+			await goto('/onboarding');
+		}
+	}
 </script>
 
 <div class="flex flex-1 flex-col overflow-hidden">
@@ -401,7 +488,69 @@
 				<p class="mt-1 text-xs text-text-secondary">{m.manage_link_expires()}</p>
 			{/if}
 		</section>
+
+		<!-- Danger zone (Fase 10.3) — admin only -->
+		<section class="mt-10 rounded-lg border border-destructive/40 p-4">
+			<h2 class="mb-2 text-[13px] font-semibold uppercase tracking-[0.05em] text-destructive">
+				{m.manage_dissolve_section()}
+			</h2>
+			<p class="mb-3 text-sm text-text-secondary">{m.manage_dissolve_blurb()}</p>
+			<button
+				type="button"
+				data-testid="dissolve-collective-button"
+				onclick={() => void openDissolve()}
+				class="rounded-md border border-destructive px-4 py-2 text-sm font-semibold text-destructive
+					hover:bg-destructive/10"
+			>
+				{m.manage_dissolve_button()}
+			</button>
+		</section>
 	{/if}
 </div>
 </div>
 </div>
+
+{#if dissolveOpen && $currentCollective}
+	<div class="fixed inset-0 z-50 flex items-center justify-center bg-black/40 p-4" data-testid="dissolve-modal">
+		<div class="w-full max-w-md rounded-lg bg-surface p-5 shadow-[0px_20px_40px_rgba(15,23,42,0.2)] dark:bg-surface-raised">
+			<h2 class="mb-2 text-base font-semibold text-slate-900 dark:text-slate-50">
+				{m.manage_dissolve_title({ name: $currentCollective.name })}
+			</h2>
+			<p class="mb-4 text-sm text-text-secondary">
+				{m.manage_dissolve_warning({ lists: listsCount, tasks: tasksCount, notes: notesCount })}
+			</p>
+			<label for="dissolve-confirm-input" class="mb-1 block text-xs font-medium text-text-secondary">
+				{m.manage_dissolve_confirm_label({ name: $currentCollective.name })}
+			</label>
+			<input
+				id="dissolve-confirm-input"
+				data-testid="dissolve-confirm-input"
+				type="text"
+				bind:value={dissolveConfirmInput}
+				class="mb-3 w-full rounded-lg border border-slate-300 bg-surface px-3 py-2 text-sm
+					focus:border-slate-500 focus:outline-none dark:border-slate-600 dark:bg-slate-800"
+			/>
+			{#if dissolveError}
+				<p class="mb-3 text-sm text-destructive" data-testid="dissolve-error">{dissolveError}</p>
+			{/if}
+			<div class="flex justify-end gap-2">
+				<button
+					type="button"
+					onclick={closeDissolve}
+					class="rounded-md px-3 py-1.5 text-sm font-medium text-slate-600 hover:bg-slate-100 dark:text-slate-300 dark:hover:bg-slate-800"
+				>
+					{m.common_cancel()}
+				</button>
+				<button
+					type="button"
+					data-testid="dissolve-confirm-button"
+					disabled={!dissolveConfirmReady || dissolveInFlight}
+					onclick={() => void confirmDissolve()}
+					class="rounded-md bg-destructive px-4 py-1.5 text-sm font-semibold text-white hover:opacity-90 disabled:opacity-50"
+				>
+					{m.manage_dissolve_confirm_button()}
+				</button>
+			</div>
+		</div>
+	</div>
+{/if}
diff --git a/apps/web/tests/e2e/dissolve-collective.test.ts b/apps/web/tests/e2e/dissolve-collective.test.ts
new file mode 100644
index 0000000..e9ed86d
--- /dev/null
+++ b/apps/web/tests/e2e/dissolve-collective.test.ts
@@ -0,0 +1,103 @@
+/**
+ * D-series: /collective/manage → dissolve (Fase 10.3, CU-H08).
+ *
+ * ⚠️ This suite must NOT dissolve the seed collective. We create an auxiliary
+ * collective per test, manipulate it, then either let the test dissolve it
+ * (D-01) or clean it up in afterEach.
+ */
+import { test, expect } from '@playwright/test';
+import { USERS } from '../fixtures/users.js';
+import { loginAs } from '../fixtures/login.js';
+import { closePool, sql } from '@colectivo/test-utils';
+
+test.describe.configure({ mode: 'serial' });
+
+const aux: { id: string | null } = { id: null };
+const auxName = `Aux dissolve ${Date.now()}`;
+
+/**
+ * Create an auxiliary collective owned (created_by) by Borja but with Ana
+ * as the sole admin (Borja is dropped from membership). This lets Ana
+ * dissolve it from the UI without touching the seed.
+ */
+async function createAuxCollective(): Promise<string> {
+	const r = await sql(
+		`INSERT INTO public.collectives (name, emoji, created_by)
+		 VALUES ($1, '💥', $2) RETURNING id`,
+		[auxName, USERS.borja.id]
+	);
+	const id = r.rows[0].id as string;
+	await sql(
+		`INSERT INTO public.collective_members (collective_id, user_id, role)
+		 VALUES ($1, $2, 'admin'), ($1, $3, 'member')`,
+		[id, USERS.ana.id, USERS.borja.id]
+	);
+	return id;
+}
+
+test.describe('Dissolve collective (CU-H08)', () => {
+	test.afterEach(async () => {
+		if (aux.id) {
+			// Best-effort cleanup if the test didn't dissolve it.
+			await sql('DELETE FROM public.collectives WHERE id = $1', [aux.id]);
+			aux.id = null;
+		}
+	});
+
+	test.afterAll(async () => {
+		await closePool();
+	});
+
+	test('D-03: Borja (member) does NOT see the dissolve button', async ({ page }) => {
+		aux.id = await createAuxCollective();
+		await loginAs(page, USERS.borja);
+		// Switch active collective to the aux one in localStorage, then reload.
+		await page.evaluate((id) => localStorage.setItem('activeCollectiveId', id), aux.id);
+		await page.goto('/collective/manage');
+		// Make sure the page is hydrated by waiting on a known member row.
+		await expect(page.getByTestId(`member-row-${USERS.ana.id}`)).toBeVisible({ timeout: 15_000 });
+		// Borja must not see the dissolve button (admin-gated).
+		await expect(page.getByTestId('dissolve-collective-button')).toHaveCount(0);
+	});
+
+	test('D-02: dissolve button disabled until input matches collective name exactly', async ({
+		page
+	}) => {
+		aux.id = await createAuxCollective();
+		await loginAs(page, USERS.ana);
+		await page.evaluate((id) => localStorage.setItem('activeCollectiveId', id), aux.id);
+		await page.goto('/collective/manage');
+		await page.getByTestId('dissolve-collective-button').click();
+
+		const confirm = page.getByTestId('dissolve-confirm-button');
+		await expect(confirm).toBeDisabled();
+
+		await page.getByTestId('dissolve-confirm-input').fill('wrong name');
+		await expect(confirm).toBeDisabled();
+
+		await page.getByTestId('dissolve-confirm-input').fill(auxName);
+		await expect(confirm).toBeEnabled();
+	});
+
+	test('D-01: Ana dissolves auxiliary collective → redirect + row gone', async ({ page }) => {
+		aux.id = await createAuxCollective();
+		await loginAs(page, USERS.ana);
+		await page.evaluate((id) => localStorage.setItem('activeCollectiveId', id), aux.id);
+		await page.goto('/collective/manage');
+		await page.getByTestId('dissolve-collective-button').click();
+
+		await page.getByTestId('dissolve-confirm-input').fill(auxName);
+		await page.getByTestId('dissolve-confirm-button').click();
+
+		// After dissolve we either land on /lists (other collectives remain) or
+		// /onboarding (no collectives). Ana still has the seed one, so /lists.
+		await expect(page).toHaveURL(/\/(lists|onboarding)$/, { timeout: 15_000 });
+
+		const r = await sql('SELECT count(*)::int AS n FROM public.collectives WHERE id = $1', [
+			aux.id
+		]);
+		expect(r.rows[0].n).toBe(0);
+		// Test cleanup already happened via cascade.
+		aux.id = null;
+	});
+});
diff --git a/supabase/migrations/018_dissolve_collective_rpc.sql b/supabase/migrations/018_dissolve_collective_rpc.sql
new file mode 100644
index 0000000..99868fb
--- /dev/null
+++ b/supabase/migrations/018_dissolve_collective_rpc.sql
@@ -0,0 +1,40 @@
+-- Migration 018: dissolve_collective(uuid) RPC — Fase 10.3 (CU-H08).
+--
+-- Permanently delete a collective and all its content. Admin-only. Errcode
+-- P0002 so the UI can distinguish "you're not admin" from generic errors.
+--
+-- All content tables that reference public.collectives.collective_id are
+-- already ON DELETE CASCADE (collective_members, collective_invitations,
+-- shopping_lists → shopping_items, task_lists → tasks, notes, item_frequency,
+-- sync_conflicts). Deleting the parent row cleans up the entire subtree.
+-- See plan/fase-10-spec-completion.md §10.3 for the audit + Riesgo 2.
+
+CREATE OR REPLACE FUNCTION public.dissolve_collective(p_collective_id uuid)
+RETURNS void
+LANGUAGE plpgsql
+SECURITY DEFINER
+SET search_path = public, auth
+AS $$
+DECLARE
+    v_user uuid := auth.uid();
+    v_role public.member_role;
+BEGIN
+    IF v_user IS NULL THEN
+        RAISE EXCEPTION 'not authenticated' USING ERRCODE = '28000';
+    END IF;
+
+    SELECT role INTO v_role
+    FROM public.collective_members
+    WHERE collective_id = p_collective_id AND user_id = v_user;
+
+    IF v_role IS DISTINCT FROM 'admin' THEN
+        RAISE EXCEPTION 'only admins can dissolve a collective'
+            USING ERRCODE = 'P0002';
+    END IF;
+
+    DELETE FROM public.collectives WHERE id = p_collective_id;
+END;
+$$;
+
+REVOKE ALL ON FUNCTION public.dissolve_collective(uuid) FROM PUBLIC;
+GRANT EXECUTE ON FUNCTION public.dissolve_collective(uuid) TO authenticated;
diff --git a/supabase/tests/011_dissolve_collective.sql b/supabase/tests/011_dissolve_collective.sql
new file mode 100644
index 0000000..88d0fbf
--- /dev/null
+++ b/supabase/tests/011_dissolve_collective.sql
@@ -0,0 +1,110 @@
+-- pgTAP: dissolve_collective() RPC — Fase 10.3 (CU-H08)
+-- Run with: psql -U postgres -d postgres -f supabase/tests/011_dissolve_collective.sql
+--
+-- Covers:
+--   * admin disolves: collective + all content cascade-deleted
+--   * member rejected (errcode P0002)
+--   * guest rejected
+--   * non-member rejected
+
+CREATE EXTENSION IF NOT EXISTS pgtap;
+
+BEGIN;
+SELECT plan(8);
+
+-- ── Existence ────────────────────────────────────────────────────────────────
+SELECT has_function(
+    'public', 'dissolve_collective', ARRAY['uuid'],
+    'public.dissolve_collective(uuid) RPC exists'
+);
+
+-- ── Setup: one collective with content, three members ────────────────────────
+INSERT INTO public.users (id, email, display_name, language, avatar_type)
+VALUES
+    ('e2000000-0000-0000-0000-000000000001', 'diss-admin@local',  'Diss Admin',  'es', 'initials'),
+    ('e2000000-0000-0000-0000-000000000002', 'diss-member@local', 'Diss Member', 'es', 'initials'),
+    ('e2000000-0000-0000-0000-000000000003', 'diss-guest@local',  'Diss Guest',  'es', 'initials')
+ON CONFLICT (id) DO NOTHING;
+
+-- Collective owned by Borja so we can delete the test admin user later.
+INSERT INTO public.collectives (id, name, emoji, created_by)
+VALUES ('cccccccc-3333-3333-3333-333333333333', 'Dissolve test', '💥',
+        '22222222-2222-2222-2222-222222222222')
+ON CONFLICT (id) DO NOTHING;
+
+INSERT INTO public.collective_members (collective_id, user_id, role)
+VALUES
+    ('cccccccc-3333-3333-3333-333333333333', 'e2000000-0000-0000-0000-000000000001', 'admin'),
+    ('cccccccc-3333-3333-3333-333333333333', 'e2000000-0000-0000-0000-000000000002', 'member'),
+    ('cccccccc-3333-3333-3333-333333333333', 'e2000000-0000-0000-0000-000000000003', 'guest')
+ON CONFLICT (collective_id, user_id) DO NOTHING;
+
+INSERT INTO public.shopping_lists (id, collective_id, name, status, created_by)
+VALUES ('cccccccc-3333-3333-3333-3333deadbeef', 'cccccccc-3333-3333-3333-333333333333',
+        'List to nuke', 'active', 'e2000000-0000-0000-0000-000000000001')
+ON CONFLICT (id) DO NOTHING;
+
+INSERT INTO public.shopping_items (list_id, name, sort_order, created_by)
+VALUES ('cccccccc-3333-3333-3333-3333deadbeef', 'Milk', 1, 'e2000000-0000-0000-0000-000000000001');
+
+-- ── Case 1: member tries to dissolve → P0002 ─────────────────────────────────
+SELECT set_config('request.jwt.claim.sub', 'e2000000-0000-0000-0000-000000000002', true);
+
+SELECT throws_ok(
+    $$ SELECT public.dissolve_collective('cccccccc-3333-3333-3333-333333333333') $$,
+    'P0002',
+    NULL,
+    'D-pgtap-a: member rejected with P0002'
+);
+
+-- ── Case 2: guest tries to dissolve → P0002 ──────────────────────────────────
+SELECT set_config('request.jwt.claim.sub', 'e2000000-0000-0000-0000-000000000003', true);
+
+SELECT throws_ok(
+    $$ SELECT public.dissolve_collective('cccccccc-3333-3333-3333-333333333333') $$,
+    'P0002',
+    NULL,
+    'D-pgtap-b: guest rejected with P0002'
+);
+
+-- ── Case 3: non-member rejected ──────────────────────────────────────────────
+SELECT set_config('request.jwt.claim.sub', '55555555-5555-5555-5555-555555555555', true); -- Eva
+
+SELECT throws_ok(
+    $$ SELECT public.dissolve_collective('cccccccc-3333-3333-3333-333333333333') $$,
+    'P0002',
+    NULL,
+    'D-pgtap-c: non-member rejected with P0002'
+);
+
+-- ── Case 4: admin succeeds + cascade ─────────────────────────────────────────
+SELECT set_config('request.jwt.claim.sub', 'e2000000-0000-0000-0000-000000000001', true);
+
+SELECT lives_ok(
+    $$ SELECT public.dissolve_collective('cccccccc-3333-3333-3333-333333333333') $$,
+    'D-pgtap-d: admin can dissolve without error'
+);
+
+SELECT is(
+    (SELECT count(*)::int FROM public.collectives
+     WHERE id = 'cccccccc-3333-3333-3333-333333333333'),
+    0,
+    'D-pgtap-d: collective row gone'
+);
+
+SELECT is(
+    (SELECT count(*)::int FROM public.shopping_lists
+     WHERE id = 'cccccccc-3333-3333-3333-3333deadbeef'),
+    0,
+    'D-pgtap-d: child shopping_list cascade-deleted'
+);
+
+SELECT is(
+    (SELECT count(*)::int FROM public.collective_members
+     WHERE collective_id = 'cccccccc-3333-3333-3333-333333333333'),
+    0,
+    'D-pgtap-d: collective_members cascade-deleted'
+);
+
+SELECT * FROM finish();
+ROLLBACK;