DUBLIN, Ireland (AP) _ An estimated 250,000 people watched the St. Patrick's Day parade in Dublin today, wearing shamrocks and waving Irish tricolor flags to honor Ireland's patron saint.

Under sunny skies, two bands, a drill team and 120 floats, sponsored by businesses and companies, paraded along the 1 1/2 -mile route from St. Stephen's Green to the main reviewing stand in O'Connell Street.

Dubliners gave a warm welcome to the estimated 1,700 foreigners, many from the United States, who took part in the parade. Another 2,000 foreign tourists lined the route to watch the festivities.

The day's celebrations kicked off with a ceremonial blessing of the shamrock in front of the reviewing stand by clergymen representing the Roman Catholic, Church of Ireland, Presbyterian and Methodist churches, and the chief rabbi of Ireland, Dr. Ephraim Mirvis.

Then, the Deputy Lord Mayor of Dublin, Alice Glenn, arrived at the stand in the lord mayor's coach. Lord Mayor Ben Briscoe is in New York for the St. Patrick's Day parade there.

Mrs. Glenn joined the minister for labor, Bertie Ahern, in reviewing the parade. He is one of the few government ministers left in Ireland.

Prime Minister Charles Haughey is in Washington, Foreign Minister Brian Lenihan is in Canada, and other ministers are in the United States and France representing Ireland at various official functions.

Mrs. Glenn said at the parade:

''We especially remember today our young emigrants who have left the country. We wish them well and hope they have a lovely day.''

The parade's grand marshal was Mike Miller from Texas, who is the executive director of the NCA Superstars drill team. The team itself, comprising 112 cheerleaders, pom pom girls and dancers, performed for the the spectators.

Eight other groups from the United States also took part in the parade. They included two bands from Illinois, the Riverview High School Kiltie band and the St. Laurence High School band.

Marching groups came from New York, Washington D.C., Michigan, Chicago, Florida and Pennsylvania.

The parade was the focus of strong media attention from abroad, with 11 television and radio crews broadcasting 30 hours of coverage to the United States and Canada.

St. Patrick's Day parades were also held in Cork, Limerick and Galway and in many other smaller towns throughout the country.

Other festivities include a traditional Irish music festival at venues around Dublin, and the Lord Mayor's St. Patrick's Day ball at the Burlington Hotel Friday night which 1,000 guests are expected to attend.