diff --git a/core/libs/prx/libkernel/Time/Time.cpp b/core/libs/prx/libkernel/Time/Time.cpp
index da55e9f2002..e029cb67d9d 100644
--- a/core/libs/prx/libkernel/Time/Time.cpp
+++ b/core/libs/prx/libkernel/Time/Time.cpp
@@ -564,10 +564,10 @@ int APS5_VABI sceKernelClockGettime(KernelClockid clock_id, KernelTimespec* tp)
     return clock_gettime_nid_postfix(static_cast<int>(clock_id), tp);
 }
 
-int APS5_VABI sceKernelConvertLocaltimeToUtc(int64_t local_time, int64_t reserved, int64_t* utc_time, KernelTimezone* timezone, int32_t* dst_seconds) {
+int APS5_VABI sceKernelConvertLocaltimeToUtc(int64_t local_time, int64_t reserved, int64_t* utc_time, KernelTimesec* timezone, int32_t* dst_seconds) {
     (void)reserved;
     if (utc_time != nullptr) *utc_time = local_time;
-    if (timezone != nullptr) *timezone = {0, 0};
+    if (timezone != nullptr) *timezone = {local_time, 0u, 0u};
     if (dst_seconds != nullptr) *dst_seconds = 0;
     return 0;
 }
diff --git a/core/libs/tests/GuestFreebsdClocks.cpp b/core/libs/tests/GuestFreebsdClocks.cpp
index 75a69daa613..25be2c623ee 100644
--- a/core/libs/tests/GuestFreebsdClocks.cpp
+++ b/core/libs/tests/GuestFreebsdClocks.cpp
@@ -1,4 +1,5 @@
 #include "SceTypes.hpp"
+#include <array>
 #include <cstdint>
 #include <cstdlib>
 
@@ -10,6 +11,8 @@ int APS5_VABI sceKernelClockGetres(KernelClockid clockId, KernelTimespec* tp);
 int APS5_VABI sceKernelUsleep_nid_postfix(KernelUseconds microseconds);
 int APS5_VABI gettimeofday_nid_postfix(KernelTimeval* tv, KernelTimezone* tz);
 std::int64_t APS5_VABI _Xtime_get_ticks_nid_postfix();
+int APS5_VABI sceKernelConvertLocaltimeToUtc(std::int64_t, std::int64_t, std::int64_t*, KernelTimesec*, std::int32_t*);
+int APS5_VABI sceKernelConvertUtcToLocaltime(std::int64_t, std::int64_t*, KernelTimesec*, std::uint64_t*);
 }
 
 static constexpr int SCE_OK = 0;
@@ -137,7 +140,35 @@ static void XtimeTicksAreGettimeofdayMicroseconds() {
     }
 }
 
+static void CalendarConversionsInitializeTheirState() {
+    constexpr std::uint64_t sentinel = 0xa5a5a5a5a5a5a5a5ull;
+    struct GuardedState {
+        std::uint64_t before;
+        KernelTimesec state;
+        std::uint64_t after;
+    };
+    for (const auto seconds : std::array<std::int64_t, 4>{-86400, 0, 1767225600, 2147483648}) {
+        GuardedState local{sentinel, {-1, 0xa5a5a5a5u, 0xa5a5a5a5u}, sentinel};
+        std::int64_t utc = -1;
+        std::int32_t dst = -1;
+        Require(sceKernelConvertLocaltimeToUtc(seconds, 0, &utc, &local.state, &dst) == SCE_OK);
+        Require(utc == seconds && dst == 0);
+        Require(local.state.t == seconds && local.state.west_sec == 0 && local.state.dst_sec == 0);
+        Require(local.before == sentinel && local.after == sentinel);
+        GuardedState universal{sentinel, {-1, 0xa5a5a5a5u, 0xa5a5a5a5u}, sentinel};
+        std::int64_t converted = -1;
+        std::uint64_t universalDst = sentinel;
+        Require(sceKernelConvertUtcToLocaltime(utc, &converted, &universal.state, &universalDst) == SCE_OK);
+        Require(converted == seconds && universalDst == 0);
+        Require(universal.state.t == seconds && universal.state.west_sec == 0 && universal.state.dst_sec == 0);
+        Require(universal.before == sentinel && universal.after == sentinel);
+    }
+    Require(sceKernelConvertLocaltimeToUtc(0, 0, nullptr, nullptr, nullptr) == SCE_OK);
+    Require(sceKernelConvertUtcToLocaltime(0, nullptr, nullptr, nullptr) == SCE_OK);
+}
+
 int main() {
+    CalendarConversionsInitializeTheirState();
     SecondClockReportsWholeSeconds();
 
     KernelTimespec time{-1, -1};