diff --git a/packages/rln/src/contract/constants.ts b/packages/rln/src/contract/constants.ts
index 636e4e16bc..a45a7b2b61 100644
--- a/packages/rln/src/contract/constants.ts
+++ b/packages/rln/src/contract/constants.ts
@@ -1,7 +1,7 @@
 import { RLN_ABI } from "./abi.js";
 
 export const LINEA_CONTRACT = {
-  chainId: 59141,
+  chainId: "59141",
   address: "0xb9cd878c90e49f797b4431fbf4fb333108cb90e6",
   abi: RLN_ABI
 };
diff --git a/packages/rln/src/contract/rln_contract.ts b/packages/rln/src/contract/rln_contract.ts
index 0aa0d81fb8..253ab65031 100644
--- a/packages/rln/src/contract/rln_contract.ts
+++ b/packages/rln/src/contract/rln_contract.ts
@@ -477,7 +477,7 @@ export class RLNContract {
         membership: {
           address,
           treeIndex: membershipId,
-          chainId: network.chainId,
+          chainId: network.chainId.toString(),
           rateLimit: decodedData.membershipRateLimit.toNumber()
         }
       };
@@ -603,7 +603,7 @@ export class RLNContract {
         membership: {
           address,
           treeIndex: membershipId,
-          chainId: network.chainId,
+          chainId: network.chainId.toString(),
           rateLimit: decodedData.membershipRateLimit.toNumber()
         }
       };
diff --git a/packages/rln/src/contract/rln_light_contract.ts b/packages/rln/src/contract/rln_light_contract.ts
index 2205c704f9..f3469f6d74 100644
--- a/packages/rln/src/contract/rln_light_contract.ts
+++ b/packages/rln/src/contract/rln_light_contract.ts
@@ -396,7 +396,7 @@ export class RLNLightContract {
         membership: {
           address,
           treeIndex: membershipId,
-          chainId: network.chainId,
+          chainId: network.chainId.toString(),
           rateLimit: decodedData.membershipRateLimit.toNumber()
         }
       };
@@ -527,7 +527,7 @@ export class RLNLightContract {
         membership: {
           address,
           treeIndex: membershipId,
-          chainId: network.chainId,
+          chainId: network.chainId.toString(),
           rateLimit: decodedData.membershipRateLimit.toNumber()
         }
       };
diff --git a/packages/rln/src/keystore/types.ts b/packages/rln/src/keystore/types.ts
index a14867c1e1..89d240edfe 100644
--- a/packages/rln/src/keystore/types.ts
+++ b/packages/rln/src/keystore/types.ts
@@ -8,7 +8,7 @@ export type Password = string | Uint8Array;
 // see reference
 // https://github.com/waku-org/nwaku/blob/f05528d4be3d3c876a8b07f9bb7dfaae8aa8ec6e/waku/waku_keystore/protocol_types.nim#L111
 export type MembershipInfo = {
-  chainId: number;
+  chainId: string;
   address: string;
   treeIndex: number;
   rateLimit: number;
diff --git a/packages/rln/src/rln.ts b/packages/rln/src/rln.ts
index ec16f79e7f..1610f1c918 100644
--- a/packages/rln/src/rln.ts
+++ b/packages/rln/src/rln.ts
@@ -197,7 +197,7 @@ export class RLNInstance {
     }
 
     const signer = options.signer || (await extractMetaMaskSigner());
-    const currentChainId = await signer.getChainId();
+    const currentChainId = (await signer.getChainId()).toString();
 
     if (chainId && chainId !== currentChainId) {
       throw Error(
@@ -312,7 +312,7 @@ export class RLNInstance {
 
     const chainId = credentials.membership.chainId;
     const network = await this._contract.provider.getNetwork();
-    const currentChainId = network.chainId;
+    const currentChainId = network.chainId.toString();
     if (chainId !== currentChainId) {
       throw Error(
         `Failed to verify chain coordinates: credentials chainID=${chainId} is not equal to registryContract chainID=${currentChainId}`
diff --git a/packages/rln/src/rln_light.ts b/packages/rln/src/rln_light.ts
index 1c2fde41be..1e9fc185e1 100644
--- a/packages/rln/src/rln_light.ts
+++ b/packages/rln/src/rln_light.ts
@@ -127,7 +127,7 @@ export class RLNLightInstance {
     }
 
     const signer = options.signer || (await extractMetaMaskSigner());
-    const currentChainId = await signer.getChainId();
+    const currentChainId = (await signer.getChainId()).toString();
 
     if (chainId && chainId !== currentChainId) {
       throw Error(