Like most Texas State Parks, there are no activity fees (unless the activity involves a rental, guided tour or lodging). There are only per person entry fees, which you can find listed on our
Guadalupe River State Park page, Texas Parks & Wildlife Department's page, and ReserveAmerica's campsite booking/reservation page (all are linked off our park page, btw.)
P.S. There are no rentals at Guadalupe River SP, so if you plan to go canoeing, bring your own canoe and gear. There is also no swimming pool; you'll be swimming in the Guadalupe River.