Irish alcohol brands have wasted no time in hijacking the festival. Take Jameson whiskey, which has been offering the chance to win a trip to Dublin.
Guinness, however, is keeping it far more simple.
Elsewhere, Tourism Ireland, through its PR firm The PC Agency, launched a stunt in London to promote travel to the the emerald isle.
Dublin Airport, which expects to welcome 376,000 passengers over the St Patrick's Day bank holiday weekend, has also gone green for the festival, lighting up the terminal in the traditional holiday colour.
Budget airline Ryanair is touting a little-known #IrishFact about its services and Leprechauns.
Food and (non-alcoholic) drink brands have also got on board, with Heck sausages paying homage to the Irish - and presumably Father Ted - with its green 'Feck' branded packs.
Confectioner Jelly Belly is offering its followers on Twitter the chance to win one kilogram of green or mixed jelly beans.
Krispy Kreme has turned its 'O'riginal' glazed doughnuts green in the US.
Meanwhile, fast food chain McDonald's has embraced the holiday by launching a limited edition mint-flavoured 'Shamrock Shake'.
Elswhere, PR firm Frank, on behalf of European online lottery company Lottoland, staged a fake visit by US President Donald Trump, whose cavalcade made it’s way to the Dail (part of the Irish Parliament) to meet Taoiseach Edna Kelly.
Google, meanwhile, is celebrating St Patrick's Day with its homage to the island of Skelling Michael.
Unsurprisingly, cheeky bookmaker Paddy Power has joined in, launching a Cheltenham Festival-themed snapchat filter.
Not strictly a brand, but what Paddy's Day roundup would be complete without a human Irish flag? Hats off to Niamh Kelly (green), Helen Kenny (white), and Emma Catchpole (orange) at PR firm Manifest.
Got a St Patrick's Day campaign you want to shout about? Let me know: firstname.lastname@example.org