How to change system timezone in Ubuntu

System timezone is first set during system installation for Ubuntu. The installer automatically selects the timezone based on your current location, though you can choose any timezone from the map for your system.

The system timezone is set using the /etc/localtime file. You can change the timezone of your Ubuntu system after installation by creating a softlink from /etc/localtime to the appropriate timezone info files available in the /usr/share/zoneinfo folder. The other method is to use a helper program such as timedatectl.

1. Launch terminal.
2. Check currently-used timezone using timedatectl.

   $ timedatectl
                  Local time: Jum 2020-08-21 09:30:04 +08   
              Universal time: Jum 2020-08-21 01:30:04 UTC   
                    RTC time: Jum 2020-08-21 01:30:04       
                   Time zone: Asia/Kuala_Lumpur (+08, +0800)
   System clock synchronized: yes                           
                 NTP service: active                        
             RTC in local TZ: no

3. Check for available timezones in the system.

   $ timedatectl list-timezones
   Africa/Abidjan
   Africa/Accra
   Africa/Algiers
   Africa/Bissau
   Africa/Cairo
   Africa/Casablanca
   Africa/Ceuta
   Africa/El_Aaiun
   Africa/Johannesburg
   Africa/Juba
   Africa/Khartoum
   ##### snipped 

4. Search for your timezone from the list of available timezones.

   $ timedatectl list-timezones | grep -i tokyo
   Asia/Tokyo

5. Set new timezone using timedatectl.

   $ sudo timedatectl set-timezone Asia/Tokyo
   [sudo] password for user:

   The above command is similar to doing the following two manual steps:

   1. Unlink your currently-used timezone.

      $ sudo unlink /etc/localtime
      [sudo] password for user:

   2. Link /etc/localtime to your new timezone.

      $ sudo ln -s /usr/share/zoneinfo/Asia/Tokyo /etc/localtime

6. Confirm changes using timedatectl.

   $ timedatectl 
                  Local time: Jum 2020-08-21 10:34:29 JST
              Universal time: Jum 2020-08-21 01:34:29 UTC
                    RTC time: Jum 2020-08-21 01:34:29    
                   Time zone: Asia/Tokyo (JST, +0900)    
   System clock synchronized: yes                        
                 NTP service: active                     
             RTC in local TZ: no