Starting next month, visitors will have to pay a fee when they go to Mackworth Island in Falmouth, Kettle Cove in Cape Elizabeth and Colonial Pemaquid in New Harbor.

The addition of staffed admission booths at the three popular spots are part of a larger plan to reduce costs and increase some fees, according to Will Harris, the director of the state Conservation Department’s Bureau of Parks and Lands.

“We’re not real happy about it, but it’s probably the best of the choices we have,” Harris said.

The change is expected to generate between $110,000 to $120,000 per season, he said.

The other measures include deferring the start date of seasonal employees and cutting 10 percent of the bureau’s maintenance budget. These measures are helping the bureau avoid layoffs and the closure of state parks, Harris said.

The admission fee will be $2 for adults who are state residents and $3 for non-resident adults. At Mackworth Island and Kettle Cove, the fee is $1 for any child between the ages of 5 and 12, with free admission for children under 5. At Colonial Pemaquid, children up to the age of 12 are free.

Fees will be collected starting May 15 at Mackworth Island and Colonial Pemaquid and May 23 at Kettle Cove.

The bureau’s policy already calls for admission fees at Colonial Pemaquid, but there is no staffed booth currently, Harris said. That site had an “iron ranger” – a pipe into which visitors can insert their admission fees – but the compliance rate is low.