Manager Giovanni Trapattoni and assistant Marco Tardelli have been making final visits to potential sites in both Poland and Ukraine this week and have settled on Gdynia, which is close to Gdansk, where they will stay at the Sheraton Sopot Hotel and train at the Municipal Stadium.
Trapattoni's side will play two of their Group C matches - against Croatia and Italy - in Poznan and will also take on world and European champions Spain in Gdansk.
Trapattoni said: "I am very happy that we have been able to secure Gdynia as a base camp for Euro 2012.
"This base meets and exceeds all of our criteria, having a good training ground, being close to the airport and being based in Poland.
"The hotel and training facilities are excellent and provide us with a well positioned base with all of the facilities required for the championships."
The Football Association of Ireland confirmed their plans after assessing 15 possible bases in the aftermath of their play-off victory over Estonia.
An FAI statement read: "The Football Association of Ireland today confirmed that it has selected its Euro 2012 base camp in Gdynia, Poland following extensive site visits to Poland and Ukraine as well as a final visit this week involving Giovanni Trapattoni and Marco Tardelli.
"The team will be located at the Sheraton Sopot Hotel which has a full range of facilities for the players during their stay.
"The Republic of Ireland will train at the Municipal Stadium in Gdynia, a new ground with a capacity of 15,000. The training facilities are of a very high standard and will provide ideal preparation for the team.
"The decision comes after site visits of more than 15 options across Poland and the Ukraine and extensive research carried out over the past three months with UEFA, the Local Organising Committee in Poland and Abbey Travel."