BOISE (AP) — Idaho’s most popular state parks started doubling camping fees for out-of-state residents on Thursday.

The intention of the fee change, mandated by a state law, was to keep Idaho residents from being crowded out of the parks.

But it will take at least a year to see if it works. That’s because this summer’s bookings for the five most popular parks were snapped up as soon as reservations opened up last fall.

“It’s kind of a scramble when the nine-month book-ahead window opens. It books up within the hour,” state parks spokesman Craig Quintana said. “The sad fact is, if we could magically snap our fingers and double our inventory, we would still sell out. We need more camping, pretty much across our system.”

Idaho State Parks reported a visitation record in 2020 of nearly 7.7 million people coming to the parks for day use and camping — 1.2 million more than the previous high number. About 30 percent of last year’s visitors were from out of state.

Idaho State Parks Director Susan Buxton said the changes will keep Idaho competitive with neighboring states, which she said have similar surcharges for non-resident campers.

“Even with these increases, our parks are a good value given the exceptional recreational opportunities,” Buxton said in a prepared statement.

At Ponderosa State Park, on the shores of Payette Lake in McCall, a basic campsite costs $24 per night and one with full hookups costs $32. Next year, if fees remain the same, out-of-staters will pay $48 and $64 for the same sites.

Those same fee increases will apply at Farragut, Priest Lake, Round Lake and Henry’s Lake.

By comparison, at California state parks on Lake Tahoe, a campsite is $45 a night at the D.L. Bliss beach campground and $35 at Sugar Pine Point. Neither has hookups.