diff --git a/.changeset/wallet-add-chain-unsupported.md b/.changeset/wallet-add-chain-unsupported.md
new file mode 100644
index 000000000..70fce4566
--- /dev/null
+++ b/.changeset/wallet-add-chain-unsupported.md
@@ -0,0 +1,6 @@
+---
+'@relayprotocol/relay-sdk': patch
+'@relayprotocol/relay-kit-ui': patch
+---
+
+Show an unsupported chain error instead of the locked-wallet message when a wallet rejects wallet_addEthereumChain
diff --git a/packages/sdk/src/utils/viemWallet.test.ts b/packages/sdk/src/utils/viemWallet.test.ts
index 163be57ec..e89c0b9dd 100644
--- a/packages/sdk/src/utils/viemWallet.test.ts
+++ b/packages/sdk/src/utils/viemWallet.test.ts
@@ -1,6 +1,26 @@
 import { describe, it, expect, vi } from 'vitest'
+import { createWalletClient, custom } from 'viem'
 import { adaptViemWallet } from './viemWallet'
 
+const INK_CHAIN_ID = 57073
+
+vi.mock('../client.js', () => ({
+  getClient: () => ({
+    chains: [
+      {
+        id: 57073,
+        viemChain: {
+          id: 57073,
+          name: 'Ink',
+          nativeCurrency: { name: 'Ether', symbol: 'ETH', decimals: 18 },
+          rpcUrls: { default: { http: ['https://rpc-gel.inkonchain.com'] } }
+        }
+      }
+    ],
+    log: vi.fn()
+  })
+}))
+
 const buildWallet = (overrides: Record<string, any> = {}) =>
   ({
     account: { address: '0x0000000000000000000000000000000000000001' },
@@ -48,3 +68,61 @@ describe('adaptViemWallet disableCapabilitiesCheck', () => {
     expect(hangingGetCapabilities).not.toHaveBeenCalled()
   })
 })
+
+describe('adaptViemWallet switchChain', () => {
+  // EIP-1193 provider that doesn't know the chain and responds to
+  // wallet_addEthereumChain with the given error (or success when undefined)
+  const buildProvider = (addChainError?: { code: number; message: string }) => ({
+    request: vi.fn(async ({ method }: { method: string }) => {
+      if (method === 'wallet_switchEthereumChain') {
+        throw Object.assign(new Error('Unrecognized chain ID "0xdef1".'), {
+          code: 4902
+        })
+      }
+      if (method === 'wallet_addEthereumChain') {
+        if (addChainError) {
+          throw Object.assign(new Error(addChainError.message), {
+            code: addChainError.code
+          })
+        }
+        return null
+      }
+      return null
+    })
+  })
+
+  const adapt = (provider: ReturnType<typeof buildProvider>) =>
+    adaptViemWallet(
+      createWalletClient({ transport: custom(provider, { retryCount: 0 }) })
+    )
+
+  it('maps a rejected wallet_addEthereumChain to an unsupported chain error (Coinbase Wallet, Ink origin)', async () => {
+    const provider = buildProvider({
+      code: -32004,
+      message: 'Method "wallet_addEthereumChain" is not supported.'
+    })
+
+    await expect(adapt(provider).switchChain(INK_CHAIN_ID)).rejects.toThrow(
+      'Wallet does not support chain'
+    )
+    expect(provider.request).toHaveBeenCalledWith(
+      expect.objectContaining({ method: 'wallet_addEthereumChain' })
+    )
+  })
+
+  it('rethrows other addChain errors unchanged', async () => {
+    const provider = buildProvider({ code: 4100, message: 'Wallet is locked' })
+
+    await expect(adapt(provider).switchChain(INK_CHAIN_ID)).rejects.toThrow(
+      'Wallet is locked'
+    )
+  })
+
+  it('resolves when addChain succeeds', async () => {
+    const provider = buildProvider()
+
+    await expect(
+      adapt(provider).switchChain(INK_CHAIN_ID)
+    ).resolves.toBeUndefined()
+  })
+})
diff --git a/packages/sdk/src/utils/viemWallet.ts b/packages/sdk/src/utils/viemWallet.ts
index 3cd8f4c28..4afde2985 100644
--- a/packages/sdk/src/utils/viemWallet.ts
+++ b/packages/sdk/src/utils/viemWallet.ts
@@ -8,7 +8,8 @@ import {
   custom,
   fallback,
   hexToBigInt,
-  http
+  http,
+  MethodNotSupportedRpcError
 } from 'viem'
 
 // Cache for expensive RPC calls (code, balance, tx count)
@@ -212,6 +213,9 @@ export const adaptViemWallet = (
               LogLevel.Verbose
             )
             return
+          } else if (e?.code === MethodNotSupportedRpcError.code) {
+            // Wallet rejects wallet_addEthereumChain (EIP-1474 code -32004)
+            throw new Error('Wallet does not support chain')
           } else {
             throw e
           }
diff --git a/packages/ui/src/components/common/ErrorWell.tsx b/packages/ui/src/components/common/ErrorWell.tsx
index 2c0e0693d..63bccfd46 100644
--- a/packages/ui/src/components/common/ErrorWell.tsx
+++ b/packages/ui/src/components/common/ErrorWell.tsx
@@ -23,9 +23,11 @@ const ErrorWell: React.FC<Props> = ({ error, hasTxHashes, fromChain }) => {
     } else if (
       error?.name &&
       (error?.message?.includes('does not support chain') ||
-        error?.message?.match(/Chain \d+ not supported/))
+        error?.message?.match(/Chain \d+ not supported/) ||
+        error?.message?.match(/wallet_addEthereumChain.*not supported/))
     ) {
-      return `Your wallet does not support ${fromChain?.displayName ?? 'this chain'}`
+      const chainName = fromChain?.displayName ?? 'this chain'
+      return `Your wallet does not support ${chainName}. Add ${chainName} to your wallet manually or connect a different wallet, then try again.`
     }
     if (
       !hasTxHashes ||
@@ -40,7 +42,7 @@ const ErrorWell: React.FC<Props> = ({ error, hasTxHashes, fromChain }) => {
       return 'Transaction Failed. Try adjusting slippage or gas limits and try again.'
     }
     return error?.message
-  }, [error?.message, hasTxHashes])
+  }, [error?.message, hasTxHashes, fromChain?.displayName])
 
   const shouldScrollErrorMessage =
     typeof renderedErrorMessage === 'string' &&