The hard reset for the Sony Xperia T3 uses the standard reset codes and system as all other Xperia mobile phones. You will note that this is for the Xperia T3 such as the D5102 mobile phone. See the reset instruction down below. Note that this will delete everything on your mobile phone including your settings.
Sony Xperia T3 Hard Reset
Please note that you need to make a backup of your content and settings as the reset will delete everything on the phone. You can use the Xperia Companion software from Sony which allows you to backup your phone. You can also use this software to reset the mobile phone via your computer while is connected via a cable. See also the Sony Xperia SL hard reset, Sony Xperia T3 hard reset as well as the Sony Xperia Z1 hard reset.
See the instructions below.
Hard Reset will erase all of your data
All described operations you are doing at your own risk.
Hard Reset Sony Xperia T3
Hard Reset Sony Xperia with the Menu
Hard Reset Sony Xperia T3 by Code