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Legal Bats


Domestic play

With regard to domestic softball play, the BSF intends to maintain the status quo for the foreseeable future.  So to be legal in the UK, a bat needs to have a Softball USA (ASA) stamp or a WBSC (ISF) stamp and not be on the Softball USA/ASA non-approved bat list.

Examples of the approved stamps are below.

However, any teams and players likely to be playing in European tournaments, and particularly the Slowpitch World Cup in 2023, should be aware that further restrictions might be in place at such events, with only bats certified by the WBSC likely to be allowed.

Please be aware of this when buying new bats!

New WBSC and USA Softball Bat Certification Stamps

Both the WBSC and USA Softball have developed updated bat certification stamps to replace their former ISF and ASA stamps.

Both the new and the former WBSC and USA Softball certification stamps will continue to be accepted, as detailed below.

World Baseball Softball Confederation

With the transition from the ISF to the WBSC, new bat certification stamps have been developed for international play.  The new logo will begin to appear on newly-manufactured bats this year; however, bats with the older 2005 stamp will continue to be accepted for competition.  Bats must also be on the WBSC certified bat list.

Certified for use in ALL levels of Fast Pitch and Slow Pitch competition.

USA Softball

USA Softball has developed new stamps to transition from their ASA 2004 and ASA 2013 stamps. These stamps are equivalent to the former stamps as shown below and will begin to appear on newly-manufactured bats beginning this season.  Bats with the older 2000, 2004 and 2013 stamps will continue to be accepted as previously.  All bats must continue to remain on the approved bat list to be certified for use.

Certified for use in ALL levels of fastpitch and slowpitch competition.

Certified for use in Adult Men’s (Under-23 and Above) fastpitch competition ONLY and all slowpitch competition.





What does COR and compression mean in simple terms? COR is the coefficient of restitution –  simply put it means that if a softball is shot at a wall at a speed of 60 mph and comes off the wall at 30 mph, then speed has been reduced by 50%, ie 0.50 COR.  If the ball comes off at 27 mph, the COR would be 0.47.

applied to squeeze the two sides of a softball by a total of a quarter inch.

A new ASA ball was introduced last year which is .52 COR and 300 compression.  This means it has a harder middle bit and a softer outside, which makes it a bit safer without reducing performance.  All balls are still legal for play if they meet ISF or ASA standards — i.e. .44/375, .47/375 or .52/300 – but the point to be aware of is that newer ASA bats could be prone to damage by 375 compression balls.

The BSF will be selling .52/300 balls this year (2015) and the BSF recommends using or switching to these balls.

However, please do not mix balls during a game – either use new or old spec.

ESF will again use the .52/300 balls at the European Slowpitch Championships in 2015.