A St. Patrick’s Day tradition in downtown Honolulu will mark its 30th anniversary today with a sea of people wearing green, drinking green (beer) and giving up green (money) in the pursuit of celebrating a saint.

As early as 11 a.m., the Murphy’s Bar & Grill St. Patrick’s Day Block Party will begin with three main food tents outside, in the parking lot diagonally across from Murphy’s, and next to O’Toole’s, Honolulu’s so-called “Irish Corner.”

One tent will offer fish and chips, burgers, hot dogs and corned-beef-and-cabbage sandwiches, said Murphy’s owner Don Murphy.

An oyster bar will offer fresh oysters, crab cakes, steamed clams and shrimp scampi, and a third food tent will offer corned beef and cabbage, steak sandwiches and lamb shanks.

During the course of the event, Murphy’s will sell 6,000 oysters, with 30 cents from each sale going to nonprofits including the Ronald McDonald House, Hospice Hawaii and the Hawaii Foodbank.

Murphy expects to serve “in excess of 3,000 pounds of corned beef” today, he said. The corned beef sales will benefit the Hawaii Children’s Cancer Foundation, which will receive $2 for each pound of corned beef sold during the week.

Murphy’s wife, Marion, is famed locally for her desserts, and for St. Paddy’s she’ll be making bread pudding, Irish whiskey cake and key lime pie, not just because it’s green, “but because it’s refreshing,” he said.

Prices will range from $8 for a hot dog with fries to $15 for Guinness-braised lamb shank, a steak sandwich or sweet chili salmon meals. Oysters start at $3 each.

A tent for keiki activities including crafts and special treats will be available from noon to 4 p.m.

Live music by Doolin Rakes and Elephant will keep the crowd entertained during the day-into-night celebration.

After 6 p.m. portions of Nuuanu Street mauka of Nimitz Highway will be closed to traffic, and music and revelers will spill into the street.

The green that celebrants spend on food and drink will go to as many as 15 nonprofit organizations, Murphy said.

Additionally, revenue generated from the event “gets us through the year. … It allows us to do the community things that we do,” he said. That includes twice-monthly lunches for Youth Outreach Waikiki, which serves the area’s homeless youths with medical care, social services and other aid.

Murphy’s Bar & Grill started staging the celebration because the establishment tended to get, well, a little busy on St. Patrick’s Day.

The crowds kept getting bigger, and now the block party is notoriously packed.