Glove (10-12.5 inch, whichever feels comfortable)
Helmet with a cage
Cleats-soccer or softball cleats- rubber OR Sneakers
(note: you can play softball with soccer cleats, but not soccer with softball cleats. Main difference is a center toe spoke on the front, used to dig in to the ground to get a good jump when starting to run)
Softball bat- Softball bats have a 2 1/4" barrel. Umpires may inspect equipment, and they should be ASA certified.
A fielding mask is also recommended.