In the Tabs system plugin settings you can set the default alignment of the tabs: Left, Right, Center, Justify or the Default (defined left or right by language RTL setting).

You can overrule this setting on a Tabs set level by adding an align parameter to the first tab tag in the set, which can have the values left, right, center or justify.

{tab title="First Tab Title" align="justify"}

Left

Right

Center

Justify