Additional tickets will go on sale for The 148th Open at Royal Portrush on 15 April, after the capacity of the venue was increased for all four days over the championship.
Portrush will stage the Open for the first time since 1951 from 18-21 July and tickets for the championship days at the Northern Irish venue sold out in record time last year, prompting The R&A to explore increasing the capacity.
The capacity for each championship day is being increased from 40,000 to 43,750 - a move that will bring the overall number of tickets for the event, including practice days, to 215,000.
Martin Slumbers, Chief Executive of The R&A, said, "From the moment tickets and hospitality packages went on sale last year it was clear that there was huge demand from fans to attend this historic occasion.
"We have been working closely with the government agencies, our advisers and contractors to assess whether we could accommodate some more fans on each day of the Championship and have decided that we can do so without impacting on the outstanding spectator experience we provide.
People can register to buy the additional tickets at TheOpen.com/Tickets.
The R&A also confirmed that golfers will be permitted to wear shorts as they practice for the final major of the year.
The organisers have relaxed their dress code for the event to allow shorts on practice days, and during final qualifying for the event.
There is the possibility of shorts being permitted on championship days, if temperatures soar on the Causeway Coast in July
In extreme weather conditions, the championship committee will reserve the right to permit the wearing of shorts.
European Tour players can already wear shorts in pro-ams and practice rounds.
Open champion Francesco Molinari said he would welcome the chance to wear shorts as he defends the title he won at Carnoustie in 2018.
Asked if would like to see the dress code relaxed on championship days, the Italian star said: "Yeah, why not, on the shorts.
"I mean, obviously, it would be a change in golf. But I don't see why not to be honest.
"There's people playing golf in shorts all around the world. So I don't see why we should be different. I'm aware that it might take time and we'll see."
Molinari joked that the championship committee would be unlikely to face extreme heat on Northern Ireland's north coast.
"I don't think it will be a priority in Portrush this summer," he said.
