diff --git a/ethers-core/src/types/transaction/eip1559.rs b/ethers-core/src/types/transaction/eip1559.rs
index 38d1d705..1b0f9a47 100644
--- a/ethers-core/src/types/transaction/eip1559.rs
+++ b/ethers-core/src/types/transaction/eip1559.rs
@@ -58,7 +58,8 @@ pub struct Eip1559TransactionRequest {
     /// baseFeePerGas + maxPriorityFeePerGas is “refunded” to the user.
     pub max_fee_per_gas: Option<U256>,
 
-    #[serde(rename = "chainId", default, skip_serializing_if = "Option::is_none")]
+    #[serde(skip_serializing)]
+    #[serde(default, rename = "chainId")]
     /// Chain ID (None for mainnet)
     pub chain_id: Option<U64>,
 }
diff --git a/ethers-core/src/types/transaction/request.rs b/ethers-core/src/types/transaction/request.rs
index 12f579cc..a581eb4c 100644
--- a/ethers-core/src/types/transaction/request.rs
+++ b/ethers-core/src/types/transaction/request.rs
@@ -42,7 +42,8 @@ pub struct TransactionRequest {
     pub nonce: Option<U256>,
 
     /// Chain ID (None for mainnet)
-    #[serde(skip_serializing_if = "Option::is_none")]
+    #[serde(skip_serializing)]
+    #[serde(default, rename = "chainId")]
     pub chain_id: Option<U64>,
 
     /////////////////  Celo-specific transaction fields /////////////////