Backyard Baseball 2006 is an entry in the Backyard Sports series and the second Baseball title in the series to be released for the GBA, following Backyard Baseball in 2002. The game uses cartoon-like visuals and carries an MLB license presenting famous players from 30 professional teams as kid versions, with 55 neighborhood kid characters in addition. Matches take place in famous stadiums, but also in backyards. The main game modes are Pick-up Game, Season Play, Mini Games and Link Play.
In Season Play a team can be taken through a season of 16 or 32 games. Typical baseball rules are followed, but there are new elements such as the ability to earn power-ups by fulfilling certain requirements, by hitting a homerun or throwing a crazy pitch. A fireball then offers an automatic strike for instance and a metal bat turns a hit into a homerun all the time. Several fields, abilities and players are unlocked gradually through the game modes and through specific actions, such as tagging out a runner, or making a double or triple play. The Mini-games mode offers challenges based around fielding and homeruns.
Compared to the first version there are improved visuals with tweaks to the gameplay. Fields are more colourful and a red target now shows where the ball will land during the fielding. There is a large amount of customization for the games, player uniforms, abilities and options such as toggling pitch locators or player stamina. There are three difficulty levels: Rookie, Pro and Allstar.