Koeman's Southampton are flying high in the Premier League, exceeding expectations to sit second in the standings ahead of Monday's trip to Aston Villa.
Southampton have defied the odds after losing a host of players and staff during the off-season, including captain Adam Lallana and manager Mauricio Pochettino, winning eight of their 11 league fixtures so far.
The south coast club are preparing to embark on a difficult festive period that brought them unstuck in 2013-14 after they won just one of nine Premier League games.
Southampton will face Crystal Palace, Chelsea and Arsenal in the space of a week heading into the New Year.
And Dutch boss Koeman is less than impressed by the scheduling, believing it will aid Southampton's Premier League rivals.
"It's difficult because I don't have experience playing that number of games in such a short time," said Koeman.
"I always used to be on holiday during Christmas and now we have a lot of games to prepare for.
"I told the players, 'Honestly, I don't have that experience', it's difficult.
"We have to play December 26 and then again on the 28th, January 1 and then January 3 for the FA Cup - it's crazy.
"It's not crazy to play at Christmas because I understand - we had that in Holland and the people like that.
"I'd like that as well if I like football and support Southampton - I can have my Christmas meal then go to the stadium and watch Southampton, I am happy.
"The problem is you have one day off between two games and that's crazy, that's impossible.
"That's my problem with the schedule because if it's the 26th and the 29th, no problem, but it's Friday and Sunday. That's crazy, one day off, crazy."
Koeman added: "Does it favour the big clubs? Yes. They can change players much easier than other teams in the Premier League.
"It is worse for the clubs who haven't got 24 players at the same level."
