diff --git a/std/os/wasi/core.zig b/std/os/wasi/core.zig
index b296b83c70..77fd831f81 100644
--- a/std/os/wasi/core.zig
+++ b/std/os/wasi/core.zig
@@ -1,18 +1,28 @@
+pub const clockid_t = u32;
 pub const errno_t = u16;
 pub const exitcode_t = u32;
 pub const fd_t = u32;
 pub const signal_t = u8;
+pub const timestamp_t = u64;
 
 pub const ciovec_t = extern struct {
     buf: [*]const u8,
     buf_len: usize,
 };
 
+pub const CLOCK_REALTIME = 0;
+pub const CLOCK_MONOTONIC = 1;
+pub const CLOCK_PROCESS_CPUTIME_ID = 2;
+pub const CLOCK_THREAD_CPUTIME_ID = 3;
+
 pub const SIGABRT: signal_t = 6;
 
 pub extern "wasi_unstable" fn args_get(argv: [*][*]u8, argv_buf: [*]u8) errno_t;
 pub extern "wasi_unstable" fn args_sizes_get(argc: *usize, argv_buf_size: *usize) errno_t;
 
+pub extern "wasi_unstable" fn clock_res_get(clock_id: clockid_t, resolution: *timestamp_t) errno_t;
+pub extern "wasi_unstable" fn clock_time_get(clock_id: clockid_t, precision: timestamp_t, timestamp: *timestamp_t) errno_t;
+
 pub extern "wasi_unstable" fn environ_get(environ: [*]?[*]u8, environ_buf: [*]u8) errno_t;
 pub extern "wasi_unstable" fn environ_sizes_get(environ_count: *usize, environ_buf_size: *usize) errno_t;