Do I need a USA Triathlon membership to race?

Yes, for any USA Triathlon-sanctioned race. Under Appendix C of the Multisport Competition Rules you must either:

• hold a valid annual USA Triathlon membership; or
• buy a single event permit for that race (USA Triathlon sets the fee and requirements).

Either way, you're bound by the full Multisport Competition Rules. Racing on purpose without a valid membership or permit can mean suspension from USA Triathlon and sanctioned events for up to one year.

You're also responsible for knowing the rules, including any race-specific exceptions, obeying officials, and self-reporting any rule you break to the Head Referee or withdrawing (section 2.2).