diff --git a/specs/gloas/beacon-chain.md b/specs/gloas/beacon-chain.md
index 6b3b40fc99..de35a52f76 100644
--- a/specs/gloas/beacon-chain.md
+++ b/specs/gloas/beacon-chain.md
@@ -11,6 +11,7 @@
   - [Domains](#domains)
   - [Misc](#misc)
   - [Withdrawal prefixes](#withdrawal-prefixes)
+  - [Builder versions](#builder-versions)
   - [Execution-layer triggered requests](#execution-layer-triggered-requests)
 - [Preset](#preset)
   - [Misc](#misc-1)
@@ -174,6 +175,12 @@ future validator withdrawal prefix may reuse this value.
 | --------------------------- | ---------------- | ------------------------------------------ |
 | `BUILDER_WITHDRAWAL_PREFIX` | `Bytes1('0x03')` | Withdrawal credential prefix for a builder |
 
+### Builder versions
+
+| Name                      | Value      | Description                              |
+| ------------------------- | ---------- | ---------------------------------------- |
+| `PAYLOAD_BUILDER_VERSION` | `uint8(0)` | Version for an execution payload builder |
+
 ### Execution-layer triggered requests
 
 | Name                           | Value            |
@@ -1538,6 +1545,8 @@ def process_execution_payload_bid(
     else:
         # Verify that the builder is active
         assert is_active_builder(state, builder_index)
+        # Verify that the builder is a payload builder
+        assert state.builders[builder_index].version == PAYLOAD_BUILDER_VERSION
         # Verify that the builder has funds to cover the bid
         assert can_builder_cover_bid(state, builder_index, amount)
         # Verify that the bid signature is valid
diff --git a/specs/gloas/builder.md b/specs/gloas/builder.md
index d033fbfdb2..2f3edd8b45 100644
--- a/specs/gloas/builder.md
+++ b/specs/gloas/builder.md
@@ -44,7 +44,8 @@ deposit contract on the execution layer, as defined in
 - `pubkey`: The builder's BLS public key.
 - `withdrawal_credentials`: The withdrawal credentials, where the first byte is
   the builder version and the last 20 bytes are the execution-layer address that
-  will receive withdrawals.
+  will receive withdrawals. For the version, execution payload builders should
+  use `PAYLOAD_BUILDER_VERSION`.
 - `amount`: At least `MIN_DEPOSIT_AMOUNT` gwei.
 - `signature`: BLS proof of possession over the corresponding `DepositMessage`
   under `DOMAIN_BUILDER_DEPOSIT`.
diff --git a/specs/gloas/fork.md b/specs/gloas/fork.md
index 1083af7ee1..6705da9458 100644
--- a/specs/gloas/fork.md
+++ b/specs/gloas/fork.md
@@ -106,7 +106,7 @@ def onboard_builders_from_pending_deposits(state: BeaconState) -> None:
             add_builder_to_registry(
                 state,
                 deposit.pubkey,
-                uint8(deposit.withdrawal_credentials[0]),
+                PAYLOAD_BUILDER_VERSION,
                 ExecutionAddress(deposit.withdrawal_credentials[12:]),
                 deposit.amount,
                 deposit.slot,
diff --git a/specs/gloas/p2p-interface.md b/specs/gloas/p2p-interface.md
index 69c3ec7a9b..ff56e5c599 100644
--- a/specs/gloas/p2p-interface.md
+++ b/specs/gloas/p2p-interface.md
@@ -369,6 +369,8 @@ where `parent_state` is the post-state of `bid.parent_block_root`, and the alias
 - _[IGNORE]_ The matching `signed_proposer_preferences` has been seen.
 - _[REJECT]_ `bid.builder_index` is a valid/active builder index -- i.e.
   `is_active_builder(state, bid.builder_index)` returns `True`.
+- _[REJECT]_ The builder version is `PAYLOAD_BUILDER_VERSION` -- i.e.
+  `state.builders[bid.builder_index].version == PAYLOAD_BUILDER_VERSION`.
 - _[REJECT]_ `bid.execution_payment == 0`.
 - _[REJECT]_ `bid.fee_recipient == proposer_preferences.fee_recipient`.
 - _[REJECT]_ The length of KZG commitments is less than or equal to the
diff --git a/tests/core/pyspec/eth_consensus_specs/test/gloas/block_processing/test_process_execution_payload_bid.py b/tests/core/pyspec/eth_consensus_specs/test/gloas/block_processing/test_process_execution_payload_bid.py
index bb34872720..ba2cdd8417 100644
--- a/tests/core/pyspec/eth_consensus_specs/test/gloas/block_processing/test_process_execution_payload_bid.py
+++ b/tests/core/pyspec/eth_consensus_specs/test/gloas/block_processing/test_process_execution_payload_bid.py
@@ -268,6 +268,43 @@ def test_process_execution_payload_bid_inactive_builder_exiting(spec, state):
     yield from run_execution_payload_bid_processing(spec, state, block, valid=False)
 
 
+@with_gloas_and_later
+@spec_state_test
+def test_process_execution_payload_bid_non_payload_builder_version(spec, state):
+    """
+    Test that a bid from a builder whose version is not PAYLOAD_BUILDER_VERSION fails.
+    """
+    next_epoch_with_full_participation(spec, state)
+    next_epoch_with_full_participation(spec, state)
+    next_epoch_with_full_participation(spec, state)
+    next_epoch_with_full_participation(spec, state)
+    assert state.finalized_checkpoint.epoch == 2
+
+    block, builder_index = prepare_block_with_non_proposer_builder(spec, state)
+    assert spec.is_active_builder(state, builder_index)
+
+    # Mark the builder as a non-payload builder, leaving every other condition valid
+    state.builders[builder_index].version = spec.uint8(spec.PAYLOAD_BUILDER_VERSION + 1)
+    assert state.builders[builder_index].version != spec.PAYLOAD_BUILDER_VERSION
+
+    # The builder can cover the bid, so the version check is the only failing condition
+    value = spec.Gwei(1000000)  # 0.001 ETH
+    assert spec.can_builder_cover_bid(state, builder_index, value)
+
+    signed_bid = prepare_signed_execution_payload_bid(
+        spec,
+        state,
+        builder_index=builder_index,
+        value=value,
+        slot=block.slot,
+        parent_block_root=block.parent_root,
+    )
+
+    block.body.signed_execution_payload_bid = signed_bid
+
+    yield from run_execution_payload_bid_processing(spec, state, block, valid=False)
+
+
 @with_gloas_and_later
 @spec_state_test
 def test_process_execution_payload_bid_self_build_non_zero_value(spec, state):
diff --git a/tests/core/pyspec/eth_consensus_specs/test/gloas/fork/test_gloas_fork_onboard_builders.py b/tests/core/pyspec/eth_consensus_specs/test/gloas/fork/test_gloas_fork_onboard_builders.py
index 1e85289516..8773c52002 100644
--- a/tests/core/pyspec/eth_consensus_specs/test/gloas/fork/test_gloas_fork_onboard_builders.py
+++ b/tests/core/pyspec/eth_consensus_specs/test/gloas/fork/test_gloas_fork_onboard_builders.py
@@ -120,6 +120,30 @@ def test_fork_single_builder_deposit(spec, phases, state):
     assert len(post_state.pending_deposits) == 0
 
 
+@with_phases(phases=[FULU], other_phases=[GLOAS])
+@spec_test
+@with_state
+@with_meta_tags(GLOAS_FORK_TEST_META_TAGS)
+def test_fork_builder_deposit_version(spec, phases, state):
+    """
+    Test that a builder onboarded at the fork is registered as a payload builder.
+    """
+    post_spec = phases[GLOAS]
+    amount = post_spec.MIN_DEPOSIT_AMOUNT
+
+    # Create a pending deposit with builder credentials
+    builder_pubkey = builder_pubkeys[0]
+    pending_deposit = create_pending_deposit_for_builder(post_spec, builder_pubkey, amount)
+    state.pending_deposits = [pending_deposit]
+
+    post_state = yield from run_fork_test(post_spec, state)
+
+    # The onboarded builder is registered with the payload builder version
+    assert len(post_state.builders) == 1
+    assert post_state.builders[0].pubkey == builder_pubkey
+    assert post_state.builders[0].version == post_spec.PAYLOAD_BUILDER_VERSION
+
+
 @with_phases(phases=[FULU], other_phases=[GLOAS])
 @spec_test
 @with_state