The parishes of St Minver and Rame Peninsula held a referendum on reserving new homes for full-time residents.
It followed a vote in St Ives last year which approved the same restrictions.
That move was challenged in the High Court by a developer but the referendum result was upheld.
Four communities in England have now adopted the restriction on second homes, including Lynton in north Devon, which voted in favour before St Ives.
The referendum was held in St Ives after the number of second homes topped 25% of the total housing stock.
St Ives estate agent Paul Le Bas said the referendum result meant developers were looking elsewhere.
But buyers were scooping up existing homes instead which still put pressure on prices, he said.
Buyers were also looking further afield in the town, away from seafront fisherman's cottages to outlying residential areas and that was having a "detrimental effect" on prices for first time buyers, he added.
Places which are not subject to the second home restriction, like Hayle, had seen more interest from developers.
"People are looking elsewhere and it was coming to that anyway because St Ives has outpriced itself," Mr Le Bas said.
"The referendum was a nudge in that direction."
Christopher Balch, professor of planning at Plymouth University, said the results at St Minver and Rame may lead to more.
"But this is a policy that's going to take five or 10 years before one can really judge whether or not it's achieved the objectives," he said.
South Hams in Devon has voted to back any town and parish in the district that attempts to do the same as St Ives.
Two Cornwall communities have voted to ban out-of-towners from buying new-build properties for use as second homes.