Station chiefs decided to launch the online service ahead of the radio launch, so potential listeners could get a sample of what's in store for them.
The station will broadcast Christmas songs around the clock and will hit the airwaves on November 28, right up until St Stephen's Day.
The temporary station was set up to raise funds for the Irish Society for the Prevention of Cruelty to Children (ISPCC), while TopGifts.ie have been instrumental in helping put the service together.
A wide mix of Christmas music, from classic artists such as Bing Crosby to more contemporary favourites like Mariah Carey is promised.
There will also be clips of memories and nostalgia from celebrities and the general public about what Christmas means to them, according to station spokesman Paul Shepherd.
Traffic and travel details will also be broadcast to help keep Dublin moving.
All monies which are raised through sponsorship of shows, premium texts and inserts will go direct to the ISPCC, and Christmas FM will be highlighting the plight of many of the less fortunate at this time of year.
The station will be live from 7am until midnight.
Many shops in Dublin city said they would be tuning into the station throughout the Christmas period.
The station can be accessed online at www.christmasfm.ie or at 89.9FM, and will be broadcast from studio facilities which were provided by D4 Hotels at the Ballsbridge Court Hotel in Dublin.
Christmas FM only has a licence for 30 days, but the station manager hopes it will become a permanent event each year.