Please note that as of January 1, 2018, Little League follows the USA Baseball Bat Standard. This means that all bats that were approved by Little League for use during the 2017 season are no longer acceptable for use in any Little League game, practice, or activity.
For more information on the USA Bat standard and a complete list of bats approved through the USABat Standard, visit usabat.com.
Before buying a new bat, make sure it has the "USA Baseball" mark as shown here:
The new bat standard DOES NOT apply to any divisions of Little League Softball. Also, there is no list of approved softball bats. In softball, the bat only needs to meet the specifications of Rule 1.10 for a softball bat.
Little League International has assembled an online resource page dedicated to baseball bat information, including the current Little League Baseball rules and regulations governing bats, definition of terms, the moratorium on the use of composite bats, and a series of frequently asked questions, with answers and licensed bat lists.