My son has been wanting to get a team together for a year and a half and has been working diligently to get a teacher sponsor so that the school will sponsor a team. He has finally found some receptive teachers and it looks like a Bass club will be forming at Wylie East High School.....for next year. In talking to him last night, he says that we can fish in THSBA tournaments without a school sponsored team? Is that true?

My son goes to a school that does not have a team and we were able to fish with another local school. All you need to do is reach out to the closest team to you and see if they will accept you to their team.

Yes and no.
It does not have to be affiliated with a "school". There are home-school teams that fish THSBA. There are also kids who fish with the nearest school that has a team in place. (Grand Saline has students from at least 3 different schools on their "Grand Saline" team. The team advisor there runs herself ragged taking care of all of her kids. She is a rockstar and a force of nature.)

I know a team that fishes with their high school on their jerseys without any sponsorship from the school.

technically, I think the school has to authorize the use of the school logo but not a lot of schools offer "sponsorship" in regards to financial backing.