Jason Bradford, 37, from Walsall, Tom Connors, 22, from Cardiff, and Brian Powell, 43, from Pontypool, were arrested near Faringdon last year.
They were held as part of a crackdown on hare coursing in Oxfordshire called Operation Migrate.
Bradford and Powell were fined £500 and ordered to pay £315 costs at Oxford Magistrates Court. Connors was fined £330 and also told to pay £315 costs.
Charges against a 15-year-old boy were dropped.