diff --git a/crates/eips/src/eip1898.rs b/crates/eips/src/eip1898.rs
index 67d675c94285..3cacd0904b0f 100644
--- a/crates/eips/src/eip1898.rs
+++ b/crates/eips/src/eip1898.rs
@@ -212,9 +212,8 @@ pub enum ParseBlockNumberError {
 }
 
 /// Error variants when parsing a [BlockNumberOrTag]
-#[cfg(feature = "std")]
-impl std::error::Error for ParseBlockNumberError {
-    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+impl core::error::Error for ParseBlockNumberError {
+    fn source(&self) -> Option<&(dyn core::error::Error + 'static)> {
         match self {
             Self::ParseIntErr(err) => std::error::Error::source(err),
             Self::ParseErr(err) => std::error::Error::source(err),
@@ -262,8 +261,7 @@ impl Display for HexStringMissingPrefixError {
     }
 }
 
-#[cfg(feature = "std")]
-impl std::error::Error for HexStringMissingPrefixError {}
+impl core::error::Error for HexStringMissingPrefixError {}
 
 /// A Block Identifier.
 /// <https://github.com/ethereum/EIPs/blob/master/EIPS/eip-1898.md>
@@ -566,9 +564,8 @@ impl Display for ParseBlockIdError {
     }
 }
 
-#[cfg(feature = "std")]
-impl std::error::Error for ParseBlockIdError {
-    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+impl core::error::Error for ParseBlockIdError {
+    fn source(&self) -> Option<&(dyn core::error::Error + 'static)> {
         match self {
             Self::ParseIntError(err) => std::error::Error::source(err),
             Self::FromHexError(err) => std::error::Error::source(err),
@@ -784,8 +781,7 @@ impl fmt::Display for ParseBlockHashOrNumberError {
     }
 }
 
-#[cfg(feature = "std")]
-impl std::error::Error for ParseBlockHashOrNumberError {}
+impl core::error::Error for ParseBlockHashOrNumberError {}
 
 impl FromStr for HashOrNumber {
     type Err = ParseBlockHashOrNumberError;
diff --git a/crates/eips/src/eip2718.rs b/crates/eips/src/eip2718.rs
index 82c11a1f7592..d8888c6860fa 100644
--- a/crates/eips/src/eip2718.rs
+++ b/crates/eips/src/eip2718.rs
@@ -52,9 +52,8 @@ impl From<Eip2718Error> for alloy_rlp::Error {
     }
 }
 
-#[cfg(feature = "std")]
-impl std::error::Error for Eip2718Error {
-    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+impl core::error::Error for Eip2718Error {
+    fn source(&self) -> Option<&(dyn core::error::Error + 'static)> {
         match self {
             Self::RlpError(err) => Some(err),
             Self::UnexpectedType(_) => None,
diff --git a/crates/eips/src/eip4844/sidecar.rs b/crates/eips/src/eip4844/sidecar.rs
index d39b9535dc66..474ac5375c9a 100644
--- a/crates/eips/src/eip4844/sidecar.rs
+++ b/crates/eips/src/eip4844/sidecar.rs
@@ -411,9 +411,9 @@ pub enum BlobTransactionValidationError {
     },
 }
 
-#[cfg(all(feature = "kzg", feature = "std"))]
-impl std::error::Error for BlobTransactionValidationError {
-    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+#[cfg(all(feature = "kzg"))]
+impl core::error::Error for BlobTransactionValidationError {
+    fn source(&self) -> Option<&(dyn core::error::Error + 'static)> {
         match self {
             Self::KZGError(source) => Some(source),
             Self::InvalidProof { .. }
diff --git a/crates/eips/src/eip4844/trusted_setup_points.rs b/crates/eips/src/eip4844/trusted_setup_points.rs
index d3795e890747..50b5e9165805 100644
--- a/crates/eips/src/eip4844/trusted_setup_points.rs
+++ b/crates/eips/src/eip4844/trusted_setup_points.rs
@@ -131,5 +131,4 @@ impl fmt::Display for KzgErrors {
     }
 }
 
-#[cfg(feature = "std")]
-impl std::error::Error for KzgErrors {}
+impl core::error::Error for KzgErrors {}
diff --git a/crates/rpc-types-engine/src/error.rs b/crates/rpc-types-engine/src/error.rs
index 9867e3a23c13..4bc853baf816 100644
--- a/crates/rpc-types-engine/src/error.rs
+++ b/crates/rpc-types-engine/src/error.rs
@@ -69,9 +69,8 @@ pub enum PayloadError {
     Decode(alloy_rlp::Error),
 }
 
-#[cfg(feature = "std")]
-impl std::error::Error for PayloadError {
-    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+impl core::error::Error for PayloadError {
+    fn source(&self) -> Option<&(dyn core::error::Error + 'static)> {
         match self {
             Self::Decode(err) => Some(err),
             _ => None,
@@ -120,5 +119,4 @@ pub enum PayloadValidationError {
     },
 }
 
-#[cfg(feature = "std")]
-impl std::error::Error for PayloadValidationError {}
+impl core::error::Error for PayloadValidationError {}
diff --git a/crates/rpc-types-engine/src/forkchoice.rs b/crates/rpc-types-engine/src/forkchoice.rs
index 142d31b1c659..6c13d2856bac 100644
--- a/crates/rpc-types-engine/src/forkchoice.rs
+++ b/crates/rpc-types-engine/src/forkchoice.rs
@@ -85,8 +85,7 @@ pub enum ForkchoiceUpdateError {
     UnknownFinalBlock,
 }
 
-#[cfg(feature = "std")]
-impl std::error::Error for ForkchoiceUpdateError {}
+impl core::error::Error for ForkchoiceUpdateError {}
 
 #[cfg(feature = "jsonrpsee-types")]
 impl From<ForkchoiceUpdateError> for jsonrpsee_types::error::ErrorObject<'static> {
diff --git a/crates/rpc-types-engine/src/jwt.rs b/crates/rpc-types-engine/src/jwt.rs
index 6cdb89f4a84b..bec9869c8db9 100644
--- a/crates/rpc-types-engine/src/jwt.rs
+++ b/crates/rpc-types-engine/src/jwt.rs
@@ -84,9 +84,8 @@ impl From<hex::FromHexError> for JwtError {
     }
 }
 
-#[cfg(feature = "std")]
-impl std::error::Error for JwtError {
-    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+impl core::error::Error for JwtError {
+    fn source(&self) -> Option<&(dyn core::error::Error + 'static)> {
         match self {
             Self::JwtSecretHexDecodeError(err) => Some(err),
             Self::CreateDir { source, .. }
diff --git a/crates/rpc-types-eth/src/block.rs b/crates/rpc-types-eth/src/block.rs
index a75cf4cb551b..cee318b150a6 100644
--- a/crates/rpc-types-eth/src/block.rs
+++ b/crates/rpc-types-eth/src/block.rs
@@ -283,9 +283,8 @@ pub enum BlockError {
     RlpDecodeRawBlock(alloy_rlp::Error),
 }
 
-#[cfg(feature = "std")]
-impl std::error::Error for BlockError {
-    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+impl core::error::Error for BlockError {
+    fn source(&self) -> Option<&(dyn core::error::Error + 'static)> {
         match self {
             Self::RlpDecodeRawBlock(err) => Some(err),
             _ => None,
diff --git a/crates/rpc-types-eth/src/filter.rs b/crates/rpc-types-eth/src/filter.rs
index 659e6a7cd10b..ab203fb9791f 100644
--- a/crates/rpc-types-eth/src/filter.rs
+++ b/crates/rpc-types-eth/src/filter.rs
@@ -165,8 +165,7 @@ pub enum FilterBlockError {
     },
 }
 
-#[cfg(feature = "std")]
-impl std::error::Error for FilterBlockError {}
+impl core::error::Error for FilterBlockError {}
 
 /// Represents the target range of blocks for the filter
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
diff --git a/crates/rpc-types-eth/src/transaction/error.rs b/crates/rpc-types-eth/src/transaction/error.rs
index eb4753f5fb31..ab3bfa317c05 100644
--- a/crates/rpc-types-eth/src/transaction/error.rs
+++ b/crates/rpc-types-eth/src/transaction/error.rs
@@ -74,9 +74,8 @@ pub enum ConversionError {
     Custom(String),
 }
 
-#[cfg(feature = "std")]
-impl std::error::Error for ConversionError {
-    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+impl core::error::Error for ConversionError {
+    fn source(&self) -> Option<&(dyn core::error::Error + 'static)> {
         match self {
             Self::Eip2718Error(err) => Some(err),
             Self::SignatureError(err) => Some(err),