diff --git a/src/core/libraries/np_manager/np_manager.cpp b/src/core/libraries/np_manager/np_manager.cpp
index e26c5a830..a60dcd86f 100644
--- a/src/core/libraries/np_manager/np_manager.cpp
+++ b/src/core/libraries/np_manager/np_manager.cpp
@@ -5,6 +5,7 @@
 #include "core/libraries/error_codes.h"
 #include "core/libraries/libs.h"
 #include "core/libraries/np_manager/np_manager.h"
+#include "core/libraries/np_manager/np_manager_error.h"
 #include "core/tls.h"
 
 namespace Libraries::NpManager {
@@ -935,14 +936,22 @@ int PS4_SYSV_ABI sceNpGetAccountDateOfBirthA() {
     return ORBIS_OK;
 }
 
-int PS4_SYSV_ABI sceNpGetAccountId() {
-    LOG_ERROR(Lib_NpManager, "(STUBBED) called");
-    return ORBIS_OK;
+int PS4_SYSV_ABI sceNpGetAccountId(OrbisNpOnlineId* online_id, u64* account_id) {
+    LOG_DEBUG(Lib_NpManager, "called");
+    if (online_id == nullptr || account_id == nullptr) {
+        return ORBIS_NP_ERROR_INVALID_ARGUMENT;
+    }
+    *account_id = 0;
+    return ORBIS_NP_ERROR_SIGNED_OUT;
 }
 
-int PS4_SYSV_ABI sceNpGetAccountIdA() {
-    LOG_ERROR(Lib_NpManager, "(STUBBED) called");
-    return ORBIS_OK;
+int PS4_SYSV_ABI sceNpGetAccountIdA(OrbisUserServiceUserId user_id, u64* account_id) {
+    LOG_DEBUG(Lib_NpManager, "user_id {}", user_id);
+    if (account_id == nullptr) {
+        return ORBIS_NP_ERROR_INVALID_ARGUMENT;
+    }
+    *account_id = 0;
+    return ORBIS_NP_ERROR_SIGNED_OUT;
 }
 
 int PS4_SYSV_ABI sceNpGetAccountLanguage() {
@@ -972,6 +981,9 @@ int PS4_SYSV_ABI sceNpGetGamePresenceStatusA() {
 
 int PS4_SYSV_ABI sceNpGetNpId(OrbisUserServiceUserId user_id, OrbisNpId* np_id) {
     LOG_DEBUG(Lib_NpManager, "user_id {}", user_id);
+    if (np_id == nullptr) {
+        return ORBIS_NP_ERROR_INVALID_ARGUMENT;
+    }
     return ORBIS_NP_ERROR_SIGNED_OUT;
 }
 
@@ -980,8 +992,11 @@ int PS4_SYSV_ABI sceNpGetNpReachabilityState() {
     return ORBIS_OK;
 }
 
-int PS4_SYSV_ABI sceNpGetOnlineId(s32 user_id, OrbisNpOnlineId* online_id) {
+int PS4_SYSV_ABI sceNpGetOnlineId(OrbisUserServiceUserId user_id, OrbisNpOnlineId* online_id) {
     LOG_DEBUG(Lib_NpManager, "user_id {}", user_id);
+    if (online_id == nullptr) {
+        return ORBIS_NP_ERROR_INVALID_ARGUMENT;
+    }
     return ORBIS_NP_ERROR_SIGNED_OUT;
 }
 
@@ -995,7 +1010,10 @@ int PS4_SYSV_ABI sceNpGetParentalControlInfoA() {
     return ORBIS_OK;
 }
 
-int PS4_SYSV_ABI sceNpGetState(s32 userId, OrbisNpState* state) {
+int PS4_SYSV_ABI sceNpGetState(OrbisUserServiceUserId user_id, OrbisNpState* state) {
+    if (state == nullptr) {
+        return ORBIS_NP_ERROR_INVALID_ARGUMENT;
+    }
     *state = OrbisNpState::SignedOut;
     LOG_DEBUG(Lib_NpManager, "Signed out");
     return ORBIS_OK;
@@ -1011,8 +1029,12 @@ int PS4_SYSV_ABI sceNpGetUserIdByOnlineId() {
     return ORBIS_OK;
 }
 
-int PS4_SYSV_ABI sceNpHasSignedUp() {
-    LOG_ERROR(Lib_NpManager, "(STUBBED) called");
+int PS4_SYSV_ABI sceNpHasSignedUp(OrbisUserServiceUserId user_id, bool* has_signed_up) {
+    LOG_DEBUG(Lib_NpManager, "called");
+    if (has_signed_up == nullptr) {
+        return ORBIS_NP_ERROR_INVALID_ARGUMENT;
+    }
+    *has_signed_up = false;
     return ORBIS_OK;
 }
 
diff --git a/src/core/libraries/np_manager/np_manager.h b/src/core/libraries/np_manager/np_manager.h
index 6ba588e5e..02a1a32f6 100644
--- a/src/core/libraries/np_manager/np_manager.h
+++ b/src/core/libraries/np_manager/np_manager.h
@@ -11,8 +11,6 @@ class SymbolsResolver;
 
 namespace Libraries::NpManager {
 
-constexpr int ORBIS_NP_ERROR_SIGNED_OUT = 0x80550006;
-
 enum class OrbisNpState : u32 { Unknown = 0, SignedOut, SignedIn };
 
 using OrbisNpStateCallbackForNpToolkit = PS4_SYSV_ABI void (*)(s32 userId, OrbisNpState state,
@@ -220,22 +218,22 @@ int PS4_SYSV_ABI sceNpGetAccountCountry();
 int PS4_SYSV_ABI sceNpGetAccountCountryA();
 int PS4_SYSV_ABI sceNpGetAccountDateOfBirth();
 int PS4_SYSV_ABI sceNpGetAccountDateOfBirthA();
-int PS4_SYSV_ABI sceNpGetAccountId();
-int PS4_SYSV_ABI sceNpGetAccountIdA();
+int PS4_SYSV_ABI sceNpGetAccountId(OrbisNpOnlineId* online_id, u64* account_id);
+int PS4_SYSV_ABI sceNpGetAccountIdA(OrbisUserServiceUserId user_id, u64* account_id);
 int PS4_SYSV_ABI sceNpGetAccountLanguage();
 int PS4_SYSV_ABI sceNpGetAccountLanguage2();
 int PS4_SYSV_ABI sceNpGetAccountLanguageA();
 int PS4_SYSV_ABI sceNpGetGamePresenceStatus();
 int PS4_SYSV_ABI sceNpGetGamePresenceStatusA();
-int PS4_SYSV_ABI sceNpGetNpId(OrbisUserServiceUserId userId, OrbisNpId* npId);
+int PS4_SYSV_ABI sceNpGetNpId(OrbisUserServiceUserId user_id, OrbisNpId* np_id);
 int PS4_SYSV_ABI sceNpGetNpReachabilityState();
-int PS4_SYSV_ABI sceNpGetOnlineId(s32 userId, OrbisNpOnlineId* onlineId);
+int PS4_SYSV_ABI sceNpGetOnlineId(OrbisUserServiceUserId user_id, OrbisNpOnlineId* online_id);
 int PS4_SYSV_ABI sceNpGetParentalControlInfo();
 int PS4_SYSV_ABI sceNpGetParentalControlInfoA();
-int PS4_SYSV_ABI sceNpGetState(s32 userId, OrbisNpState* state);
+int PS4_SYSV_ABI sceNpGetState(OrbisUserServiceUserId user_id, OrbisNpState* state);
 int PS4_SYSV_ABI sceNpGetUserIdByAccountId();
 int PS4_SYSV_ABI sceNpGetUserIdByOnlineId();
-int PS4_SYSV_ABI sceNpHasSignedUp();
+int PS4_SYSV_ABI sceNpHasSignedUp(OrbisUserServiceUserId user_id, bool* has_signed_up);
 int PS4_SYSV_ABI sceNpIdMapperAbortRequest();
 int PS4_SYSV_ABI sceNpIdMapperAccountIdToNpId();
 int PS4_SYSV_ABI sceNpIdMapperAccountIdToOnlineId();
diff --git a/src/core/libraries/np_manager/np_manager_error.h b/src/core/libraries/np_manager/np_manager_error.h
new file mode 100644
index 000000000..4af0d08ef
--- /dev/null
+++ b/src/core/libraries/np_manager/np_manager_error.h
@@ -0,0 +1,9 @@
+// SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "core/libraries/error_codes.h"
+
+constexpr int ORBIS_NP_ERROR_INVALID_ARGUMENT = 0x80550003;
+constexpr int ORBIS_NP_ERROR_SIGNED_OUT = 0x80550006;
\ No newline at end of file