diff --git a/api-v3/src/database/migrations/1789844900000-phase-f3-1-finding-catalog-merge.ts b/api-v3/src/database/migrations/1789844900000-phase-f3-1-finding-catalog-merge.ts
new file mode 100644
index 0000000..30b728d
--- /dev/null
+++ b/api-v3/src/database/migrations/1789844900000-phase-f3-1-finding-catalog-merge.ts
@@ -0,0 +1,46 @@
+import { MigrationInterface, QueryRunner } from 'typeorm';
+
+export class PhaseF31FindingCatalogMerge1789844900000 implements MigrationInterface {
+  name = 'PhaseF31FindingCatalogMerge1789844900000';
+
+  public async up(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(`
+      CREATE TABLE finding_catalog_item_merges (
+        id uuid PRIMARY KEY DEFAULT gen_random_uuid(),
+        source_item_id uuid NOT NULL REFERENCES finding_catalog_items(id) ON DELETE RESTRICT,
+        canonical_item_id uuid NOT NULL REFERENCES finding_catalog_items(id) ON DELETE RESTRICT,
+        reason text NOT NULL,
+        merged_at timestamptz NOT NULL DEFAULT CURRENT_TIMESTAMP,
+        merged_by uuid NULL REFERENCES users(id) ON DELETE SET NULL,
+        request_id varchar(128) NULL,
+        source_snapshot jsonb NOT NULL,
+        canonical_snapshot jsonb NOT NULL,
+        CONSTRAINT chk_finding_catalog_item_merges_distinct CHECK (source_item_id <> canonical_item_id),
+        CONSTRAINT uq_finding_catalog_item_merges_source UNIQUE (source_item_id)
+      )
+    `);
+    await queryRunner.query(`CREATE INDEX idx_finding_catalog_item_merges_canonical ON finding_catalog_item_merges(canonical_item_id)`);
+    await queryRunner.query(`CREATE INDEX idx_finding_catalog_item_merges_at ON finding_catalog_item_merges(merged_at)`);
+    await queryRunner.query(`
+      CREATE OR REPLACE FUNCTION protect_finding_catalog_item_merges_append_only()
+      RETURNS trigger
+      LANGUAGE plpgsql
+      AS $$
+      BEGIN
+        RAISE EXCEPTION 'finding_catalog_item_merges es append-only; una fusión de catálogo no puede editarse ni borrarse';
+      END;
+      $$
+    `);
+    await queryRunner.query(`
+      CREATE TRIGGER trg_finding_catalog_item_merges_append_only
+      BEFORE UPDATE OR DELETE ON finding_catalog_item_merges
+      FOR EACH ROW EXECUTE FUNCTION protect_finding_catalog_item_merges_append_only()
+    `);
+  }
+
+  public async down(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query('DROP TRIGGER IF EXISTS trg_finding_catalog_item_merges_append_only ON finding_catalog_item_merges');
+    await queryRunner.query('DROP FUNCTION IF EXISTS protect_finding_catalog_item_merges_append_only()');
+    await queryRunner.query('DROP TABLE IF EXISTS finding_catalog_item_merges');
+  }
+}