diff --git a/modules/bitgo/test/v2/unit/staking/stakingWalletCommon.ts b/modules/bitgo/test/v2/unit/staking/stakingWalletCommon.ts
index 80ddab3997..81aabd61c8 100644
--- a/modules/bitgo/test/v2/unit/staking/stakingWalletCommon.ts
+++ b/modules/bitgo/test/v2/unit/staking/stakingWalletCommon.ts
@@ -84,6 +84,54 @@ describe('Staking Wallet Common', function () {
       msScope.isDone().should.be.True();
     });
 
+    it('should forward top-level staking subtype to staking-service', async function () {
+      const expected = fixtures.stakingRequest([fixtures.transaction('NEW')]);
+      const msScope = nock(microservicesUri)
+        .post(`/api/staking/v1/${stakingWallet.coin}/wallets/${stakingWallet.walletId}/requests`, {
+          amount: '1',
+          clientId: 'clientId',
+          subType: 'ETH_STAKE_PECTRA',
+          type: 'STAKE',
+        })
+        .reply(201, expected);
+
+      const stakingRequest = await stakingWallet.stake({
+        amount: '1',
+        clientId: 'clientId',
+        subType: 'ETH_STAKE_PECTRA',
+      });
+
+      should.exist(stakingRequest);
+      stakingRequest.should.deepEqual(expected);
+      msScope.isDone().should.be.True();
+    });
+
+    it('should preserve the legacy PoX-5 subtype on the wire', async function () {
+      const expected = fixtures.stakingRequest([fixtures.transaction('NEW')]);
+      const msScope = nock(microservicesUri)
+        .post(`/api/staking/v1/${stakingWallet.coin}/wallets/${stakingWallet.walletId}/requests`, {
+          amount: '1',
+          bondIndex: 0,
+          clientId: 'clientId',
+          signerManager: 'manager',
+          subType: 'pox5-bond',
+          type: 'STAKE',
+        })
+        .reply(201, expected);
+
+      const stakingRequest = await stakingWallet.stake({
+        amount: '1',
+        bondIndex: 0,
+        clientId: 'clientId',
+        signerManager: 'manager',
+        subType: 'pox5-bond',
+      });
+
+      should.exist(stakingRequest);
+      stakingRequest.should.deepEqual(expected);
+      msScope.isDone().should.be.True();
+    });
+
     it('should call staking-service to stake with optional stakeMany parameters', async function () {
       const expected = fixtures.stakingRequest([fixtures.transaction('NEW')]);
       const msScope = nock(microservicesUri)
diff --git a/modules/sdk-core/src/bitgo/staking/iStakingWallet.ts b/modules/sdk-core/src/bitgo/staking/iStakingWallet.ts
index ec7c8ef90f..0010b4f7ed 100644
--- a/modules/sdk-core/src/bitgo/staking/iStakingWallet.ts
+++ b/modules/sdk-core/src/bitgo/staking/iStakingWallet.ts
@@ -1,6 +1,34 @@
 import { SignedTransaction } from '../baseCoin';
 import { PrebuildTransactionOptions, PrebuildTransactionResult } from '../wallet';
 
+/**
+ * All known staking subtypes across coins.
+ * Used by StakeOptions.subType for compile-time type safety.
+ */
+export type StakingSubType =
+  | 'STAKE'
+  | 'ETH_STAKE_PECTRA'
+  | 'LIDO'
+  | 'SOL_STAKE'
+  | 'MARINADE'
+  | 'MARINADE_SELECT'
+  | 'NATIVE_STAKE'
+  | 'INFRARED_LIQUID_STAKE'
+  | 'WCT_STAKE'
+  | 'STACK'
+  | 'SELF_STACK'
+  | 'MULTI_NOMINATOR_STAKE'
+  | 'SINGLE_NOMINATOR_STAKE'
+  | 'TON_WHALES'
+  | 'VET_VALIDATOR_REGISTRATION'
+  | 'VET_UNSTAKE'
+  | 'VET_INCREASE_STAKE'
+  | 'STAVAX_STAKE'
+  | 'PSTAVAX_STAKE'
+  | 'WFLR_STAKE'
+  | 'VOTE'
+  | 'pox5-bond';
+
 export interface StakingRequest {
   id: string;
   amount: string;
@@ -88,9 +116,10 @@ export interface StakeOptions {
    */
   blsSignature?: string;
   /**
-   * subtype-specific interfaces provide their own discriminant
+   * coin-specific staking subtype, forwarded to staking-service.
+   * Restricted to known values via StakingSubType union.
    */
-  subType?: never;
+  subType?: StakingSubType;
   /**
    * stx btc reward address
    */
@@ -214,9 +243,10 @@ export interface UnstakeOptions {
   clientId?: string;
   delegationId?: string;
   /**
-   * coin sepcific staking subtype
+   * coin-specific staking subtype for unstaking.
+   * Restricted to known values via StakingSubType union.
    */
-  subType?: string;
+  subType?: StakingSubType;
 }
 
 export interface EthUnstakeOptions {