The Saskatchewan government says so many people tried to book campsites this week that the online reservations system had problems and over-charged some of them.
The first round of parks were available for booking Monday morning.
The government says the high volume of campers going online to nab sites quickly contributed to a processing error.
It says of the approximately 7,000 reservations that were completed, about 1,500 people were charged more than once for their campsites.
Staff with the Ministry of Parks, Culture and Sport have emailed apologies and said the problem was fixed in time for Wednesday's bookings.
The government said about 3,400 people made camping reservations in 90 minutes Wednesday morning and the billing error was not repeated.