diff --git a/ape_infura/provider.py b/ape_infura/provider.py
index ca5515c..8a0067a 100644
--- a/ape_infura/provider.py
+++ b/ape_infura/provider.py
@@ -8,8 +8,10 @@
 from ape_ethereum.provider import Web3Provider
 from web3 import HTTPProvider, Web3
 from web3.exceptions import ContractLogicError as Web3ContractLogicError
+from web3.exceptions import ExtraDataLengthError
 from web3.gas_strategies.rpc import rpc_gas_price_strategy
 from web3.middleware import geth_poa_middleware
+from web3.middleware.validation import MAX_EXTRADATA_LENGTH
 
 _ENVIRONMENT_VARIABLE_NAMES = ("WEB3_INFURA_PROJECT_ID", "WEB3_INFURA_API_KEY")
 # NOTE: https://docs.infura.io/learn/websockets#supported-networks
@@ -94,7 +96,17 @@ def connection_str(self) -> str:
         return self.uri
 
     def connect(self):
-        self._web3 = Web3(HTTPProvider(self.uri))
+        self._web3 = _create_web3(HTTPProvider(self.uri))
+
+        if self._needs_poa_middleware:
+            self._web3.middleware_onion.inject(geth_poa_middleware, layer=0)
+
+        self._web3.eth.set_gas_price_strategy(rpc_gas_price_strategy)
+
+    @property
+    def _needs_poa_middleware(self) -> bool:
+        if self._web3 is None:
+            return False
 
         # Any chain that *began* as PoA needs the middleware for pre-merge blocks
         optimism = (10, 420)
@@ -103,9 +115,21 @@ def connect(self):
         blast = (11155111, 168587773)
 
         if self._web3.eth.chain_id in (*optimism, *polygon, *linea, *blast):
-            self._web3.middleware_onion.inject(geth_poa_middleware, layer=0)
+            return True
 
-        self._web3.eth.set_gas_price_strategy(rpc_gas_price_strategy)
+        for block_id in ("earliest", "latest"):
+            try:
+                block = self.web3.eth.get_block(block_id)  # type: ignore
+            except ExtraDataLengthError:
+                return True
+            else:
+                if (
+                    "proofOfAuthorityData" in block
+                    or len(block.get("extraData", "")) > MAX_EXTRADATA_LENGTH
+                ):
+                    return True
+
+        return False
 
     def disconnect(self):
         """
@@ -149,3 +173,7 @@ def get_virtual_machine_error(self, exception: Exception, **kwargs) -> VirtualMa
                 return ContractLogicError(txn=txn)
 
         return VirtualMachineError(message, txn=txn)
+
+
+def _create_web3(http_provider: HTTPProvider) -> Web3:
+    return Web3(http_provider)
diff --git a/ape_infura/utils.py b/ape_infura/utils.py
index 35a4fda..05efd36 100644
--- a/ape_infura/utils.py
+++ b/ape_infura/utils.py
@@ -12,6 +12,7 @@
         "sepolia",
     ],
     "ethereum": [
+        "holesky",
         "mainnet",
         "sepolia",
     ],
diff --git a/tests/test_provider.py b/tests/test_provider.py
index bddbe28..cfdbaf1 100644
--- a/tests/test_provider.py
+++ b/tests/test_provider.py
@@ -2,7 +2,10 @@
 
 import pytest
 import websocket  # type: ignore
+from ape import networks
 from ape.utils import ZERO_ADDRESS
+from web3.exceptions import ExtraDataLengthError
+from web3.middleware import geth_poa_middleware
 
 from ape_infura.provider import _WEBSOCKET_CAPABLE_ECOSYSTEMS, Infura
 
@@ -93,3 +96,14 @@ def test_uri_with_random_api_key(provider, mocker):
 
     # Disconnect so key isn't cached.
     provider.disconnect()
+
+
+def test_dynamic_poa_check(mocker):
+    real = networks.ethereum.holesky.get_provider("infura")
+    mock_web3 = mocker.MagicMock()
+    mock_web3.eth.get_block.side_effect = ExtraDataLengthError
+    infura = Infura(name=real.name, network=real.network)
+    patch = mocker.patch("ape_infura.provider._create_web3")
+    patch.return_value = mock_web3
+    infura.connect()
+    mock_web3.middleware_onion.inject.assert_called_once_with(geth_poa_middleware, layer=0)