Next week's Irish Open at Royal Portrush is a sell-out - the first time that has happened on the European Tour outside of the majors.
The tournament hasn't been held in Northern Ireland since 1953 and with local heroes and recent major winners Rory McIlroy, Darren Clarke and Graeme McDowell all taking part, expectation is enormous.
Northern Ireland Tourist Board chief executive Alan Clarke said: "This year's Irish Open is sure to be one of the biggest in the competition's history with advance ticket sales reaching unprecedented levels and record crowds expected.
"While in previous years it may have been possible for spectators to turn up on the day and purchase tickets on the day, we would strongly urge people not to try this on Saturday and Sunday as the event is completely sold out at the weekend and there is absolutely no chance of being admitted without a ticket."
"We are preparing for a crowd around the 100,000 mark for the week," added championship director Antonia Beggs.
In addition to normal scheduled services, extra trains will run from Belfast and Derry/Londonderry to Portrush and there are dedicated coaches from various locations.
Three-time major winner Padraig Harrington and USPGA champion Keegan Bradley are also taking part.