diff --git a/README.md b/README.md
index 5e37b8f6..92f26936 100644
--- a/README.md
+++ b/README.md
@@ -166,7 +166,7 @@ Returns the Solana address you should send SOL to in order to deposit. When `own
 
 ```sh
 icp canister call -e prod cksol_minter get_deposit_address \
-  '(record { owner = null; subaccount = null })' --query
+  '(record { owner = null; subaccount = null })'
 ```
 
 ### Notify the minter of a deposit
diff --git a/integration_tests/src/lib.rs b/integration_tests/src/lib.rs
index 53c291d9..e4a28f48 100644
--- a/integration_tests/src/lib.rs
+++ b/integration_tests/src/lib.rs
@@ -376,7 +376,7 @@ impl CkSolMinter<'_> {
         &self,
         args: impl Into<GetDepositAddressArgs>,
     ) -> Result<Address, String> {
-        self.try_query_call("get_deposit_address", (args.into(),))
+        self.try_update_call("get_deposit_address", (args.into(),), 0)
             .await
     }
 
diff --git a/minter/cksol_minter.did b/minter/cksol_minter.did
index f81e36f2..b6ce2f14 100644
--- a/minter/cksol_minter.did
+++ b/minter/cksol_minter.did
@@ -467,7 +467,7 @@ service : (MinterArg) -> {
     //
     // If the owner is not set, it defaults to the caller's principal.
     // The resolved owner must be a non-anonymous principal.
-    get_deposit_address: (GetDepositAddressArgs) -> (Address) query;
+    get_deposit_address: (GetDepositAddressArgs) -> (Address);
 
     // Register an account for automated deposit monitoring.
     //
diff --git a/minter/src/address/mod.rs b/minter/src/address/mod.rs
index 00ec5729..44323163 100644
--- a/minter/src/address/mod.rs
+++ b/minter/src/address/mod.rs
@@ -13,11 +13,9 @@ mod tests;
 pub(crate) type DerivationPath = Vec<Vec<u8>>;
 
 /// Implementation of the `get_deposit_address` canister endpoint.
-/// Because the endpoint is a query, it must be synchronous and cannot fetch the
-/// master key on demand — it traps if the key has not yet been initialized.
-pub fn get_deposit_address(account: &Account) -> Address {
-    let master_key = read_state(|s| s.minter_public_key().cloned())
-        .unwrap_or_else(|| ic_cdk::trap("master key not yet initialized"));
+/// Fetches the Schnorr master key lazily if not yet cached.
+pub async fn get_deposit_address<R: CanisterRuntime>(runtime: &R, account: &Account) -> Address {
+    let master_key = lazy_get_schnorr_master_key(runtime).await;
     account_address(&master_key, account)
 }
 
diff --git a/minter/src/address/tests.rs b/minter/src/address/tests.rs
index 5a471dc1..73d8c9d8 100644
--- a/minter/src/address/tests.rs
+++ b/minter/src/address/tests.rs
@@ -84,24 +84,30 @@ mod lazy_schnorr_master_key {
 mod get_deposit_address_tests {
     use super::*;
 
-    #[test]
-    fn returns_address_when_key_is_cached() {
+    #[tokio::test]
+    async fn returns_address_when_key_is_cached() {
         init_state();
         init_schnorr_master_key();
+        let runtime = TestCanisterRuntime::new();
         let master_key = read_state(|s| s.minter_public_key().cloned().unwrap());
         let acc = account(1);
 
         assert_eq!(
-            get_deposit_address(&acc),
+            get_deposit_address(&runtime, &acc).await,
             account_address(&master_key, &acc),
         );
     }
 
-    #[test]
-    #[should_panic]
-    fn traps_when_key_is_not_cached() {
+    #[tokio::test]
+    async fn fetches_key_when_not_cached() {
         init_state();
-        get_deposit_address(&account(1));
+        let runtime = TestCanisterRuntime::new().with_schnorr_public_key(test_key_result());
+        let acc = account(1);
+
+        assert_eq!(
+            get_deposit_address(&runtime, &acc).await,
+            account_address(&test_key(), &acc),
+        );
     }
 }
 
diff --git a/minter/src/main.rs b/minter/src/main.rs
index 4d144410..8cc8ccc0 100644
--- a/minter/src/main.rs
+++ b/minter/src/main.rs
@@ -59,10 +59,12 @@ fn post_upgrade(args: Option<MinterArg>) {
     setup_timers();
 }
 
-#[ic_cdk::query]
-fn get_deposit_address(args: GetDepositAddressArgs) -> Address {
+#[ic_cdk::update]
+async fn get_deposit_address(args: GetDepositAddressArgs) -> Address {
     let account = assert_non_anonymous_account(args.owner, args.subaccount);
-    cksol_minter::address::get_deposit_address(&account).into()
+    cksol_minter::address::get_deposit_address(&IcCanisterRuntime::new(), &account)
+        .await
+        .into()
 }
 
 #[ic_cdk::update]