Which bats are legal, and what happens if a player uses an illegal one?

Q: Which bats are legal, and what happens if a player uses an illegal one?

Under Rule 3, Section 1, a legal bat must: be no longer than 34 inches, no heavier than 38 ounces, and no more than 2.25 inches in diameter at its largest part, carry the USA Softball certification mark that is allowed in all games. The other mark is only legal in slow pitch, men's and boys' fastpitch and men's modified, so it can't be used in girls fastpitch, appear on USA Softball's list of approved bat models, and not on its Non-Approved Bat List, have a safety grip 6 to 15 inches from the knob, a knob at least 1.6 inches across, and no dents, cracks, burrs or rattles. Altered bats are illegal: rolled, shaved, repainted, weighted, heated, cooled or otherwise modified. A name or number laser-marked or painted on the bat is fine. Since 2026, a bat sensor is allowed if it's properly attached. Penalties (Rule 7, Section 6): Batter caught with an altered or non-approved bat: out and ejected. Batter caught with an otherwise illegal bat (for example, damaged): out. If it's discovered after her at-bat but before the next pitch, she's out, any outs on the play stand, and other runners go back to their bases.

Question

Accepted Answer

Under Rule 3, Section 1, a legal bat must:

be no longer than 34 inches, no heavier than 38 ounces, and no more than 2.25 inches in diameter at its largest part,
carry the USA Softball certification mark that is allowed in all games. The other mark is only legal in slow pitch, men's and boys' fastpitch and men's modified, so it can't be used in girls fastpitch,
appear on USA Softball's list of approved bat models, and not on its Non-Approved Bat List,
have a safety grip 6 to 15 inches from the knob, a knob at least 1.6 inches across, and no dents, cracks, burrs or rattles.

Altered bats are illegal: rolled, shaved, repainted, weighted, heated, cooled or otherwise modified. A name or number laser-marked or painted on the bat is fine. Since 2026, a bat sensor is allowed if it's properly attached.

Penalties (Rule 7, Section 6):

Batter caught with an altered or non-approved bat: out and ejected.
Batter caught with an otherwise illegal bat (for example, damaged): out.
If it's discovered after her at-bat but before the next pitch, she's out, any outs on the play stand, and other runners go back to their bases.