Arimaa Android App by David Wu

Whether you are new to Arimaa or an advanced player you will find this app a must. This app allows you to play Arimaa with a friend or against a computer opponent and includes an in-app rules explanation for new players. The computer opponent is a version of the same bot that won the 2011 Arimaa Computer Championship. While significantly weaker on the hardware of a phone or tablet, the computer can still provide excellent practice for beginning and intermediate-level players, and has a difficulty level that can easily be adjusted.

Features include:

Play Arimaa with 1 player against the computer or with 2 players.
Built-in rules explanation
11 difficulty levels for the computer
Ability to save, load, and view games.

Search the Google app store for 'arimaa'.

Looking for the iPhone app.