diff --git a/packages/client-engine-runtime/src/transaction-manager/transaction-manager.ts b/packages/client-engine-runtime/src/transaction-manager/transaction-manager.ts
index 5e4bddab6fcf..810b9c049ae5 100644
--- a/packages/client-engine-runtime/src/transaction-manager/transaction-manager.ts
+++ b/packages/client-engine-runtime/src/transaction-manager/transaction-manager.ts
@@ -300,28 +300,30 @@ export class TransactionManager {
   }
 
   async commitTransaction(transactionId: string): Promise<void> {
-    return await this.tracingHelper.runInChildSpan('commit_transaction', async () => {
-      await this.#withActiveTransactionLock(transactionId, 'commit', async (txw) => {
-        if (txw.depth > 1) {
-          if (!txw.transaction) throw new TransactionNotFoundError()
-          const savepointName = txw.savepoints.at(-1)
-          if (!savepointName) {
-            throw new TransactionInternalConsistencyError(
-              `Missing savepoint for nested commit. Depth: ${txw.depth}, transactionId: ${txw.id}`,
-            )
-          }
-          try {
-            await this.#releaseSavepoint(txw.transaction, savepointName)
-          } finally {
-            // Keep internal state consistent even if releasing the savepoint fails.
-            txw.savepoints.pop()
-            txw.depth -= 1
+    return await this.tracingHelper
+      .runInChildSpan('commit_transaction', async () => {
+        await this.#withActiveTransactionLock(transactionId, 'commit', async (txw) => {
+          if (txw.depth > 1) {
+            if (!txw.transaction) throw new TransactionNotFoundError()
+            const savepointName = txw.savepoints.at(-1)
+            if (!savepointName) {
+              throw new TransactionInternalConsistencyError(
+                `Missing savepoint for nested commit. Depth: ${txw.depth}, transactionId: ${txw.id}`,
+              )
+            }
+            try {
+              await this.#releaseSavepoint(txw.transaction, savepointName)
+            } finally {
+              // Keep internal state consistent even if releasing the savepoint fails.
+              txw.savepoints.pop()
+              txw.depth -= 1
+            }
+            return
           }
-          return
-        }
-        await this.#closeTransaction(txw, 'committed')
+          await this.#closeTransaction(txw, 'committed')
+        })
       })
-    })
+      .catch(rethrowAsUserFacing)
   }
 
   async rollbackTransaction(transactionId: string): Promise<void> {
diff --git a/packages/client/tests/functional/issues/30580/_matrix.ts b/packages/client/tests/functional/issues/30580/_matrix.ts
new file mode 100644
index 000000000000..05f57793d4c0
--- /dev/null
+++ b/packages/client/tests/functional/issues/30580/_matrix.ts
@@ -0,0 +1,11 @@
+import { defineMatrix } from '../../_utils/defineMatrix'
+import { Providers } from '../../_utils/providers'
+
+export default defineMatrix(() => [
+  [
+    {
+      driverAdapter: 'js_pg',
+      provider: Providers.POSTGRESQL,
+    },
+  ],
+])
diff --git a/packages/client/tests/functional/issues/30580/prisma/_schema.ts b/packages/client/tests/functional/issues/30580/prisma/_schema.ts
new file mode 100644
index 000000000000..5d6733ec6428
--- /dev/null
+++ b/packages/client/tests/functional/issues/30580/prisma/_schema.ts
@@ -0,0 +1,20 @@
+import { idForProvider } from '../../../_utils/idForProvider'
+import testMatrix from '../_matrix'
+
+export default testMatrix.setupSchema(({ provider }) => {
+  return /* Prisma */ `
+    generator client {
+      provider = "prisma-client-js"
+    }
+
+    datasource db {
+      provider = "${provider}"
+    }
+
+    model AppSetting {
+      id    ${idForProvider(provider)}
+      key   String @unique
+      value String
+    }
+  `
+})
diff --git a/packages/client/tests/functional/issues/30580/tests.ts b/packages/client/tests/functional/issues/30580/tests.ts
new file mode 100644
index 000000000000..0e40ef25cd16
--- /dev/null
+++ b/packages/client/tests/functional/issues/30580/tests.ts
@@ -0,0 +1,76 @@
+import testMatrix from './_matrix'
+// @ts-ignore
+import type { PrismaClient } from './generated/prisma/client'
+
+declare let prisma: PrismaClient
+
+testMatrix.setupTestSuite(
+  () => {
+    beforeEach(async () => {
+      await prisma.appSetting.deleteMany()
+    })
+
+    test('commit-time write conflicts are surfaced as P2034', async () => {
+      const prefix = 'probe-'
+      let reads = 0
+      let releaseReads!: () => void
+      const readsCompleted = new Promise<void>((resolve) => {
+        releaseReads = resolve
+      })
+      let completedInserts = 0
+      let successfulInserts = 0
+      let releaseInserts!: () => void
+      const insertsCompleted = new Promise<void>((resolve) => {
+        releaseInserts = resolve
+      })
+
+      const run = (suffix: number) =>
+        prisma.$transaction(
+          async (tx) => {
+            await tx.appSetting.count({ where: { key: { startsWith: prefix } } })
+
+            reads += 1
+            if (reads === 2) releaseReads()
+            await readsCompleted
+
+            try {
+              await tx.appSetting.create({
+                data: { key: `${prefix}${suffix}`, value: 'x' },
+              })
+              successfulInserts += 1
+            } finally {
+              // Always release the post-insert barrier once both attempts have
+              // completed, even if one insert fails before COMMIT.
+              completedInserts += 1
+              if (completedInserts === 2) releaseInserts()
+            }
+
+            await insertsCompleted
+          },
+          { isolationLevel: 'Serializable' },
+        )
+
+      const results = await Promise.allSettled([run(1), run(2)])
+      const rejected = results.filter((r) => r.status === 'rejected')
+      const fulfilled = results.filter((r) => r.status === 'fulfilled')
+
+      expect(successfulInserts).toBe(2)
+      expect(fulfilled).toHaveLength(1)
+      expect(rejected).toHaveLength(1)
+      expect(rejected[0]).toMatchObject({
+        reason: {
+          name: 'PrismaClientKnownRequestError',
+          code: 'P2034',
+        },
+      })
+
+      await expect(prisma.appSetting.count()).resolves.toBe(1)
+    })
+  },
+  {
+    optOut: {
+      from: ['mongodb', 'mysql', 'sqlite', 'sqlserver', 'cockroachdb'],
+      reason: 'Serializable write skew surfaced as SQLSTATE 40001 at COMMIT is the PostgreSQL behavior from the issue',
+    },
+  },
+)