The Eastern Regional Championships are second only in size to the New Zealand Surf Lifesaving Championships which take place in early March.
Surf Lifesaving New Zealand Eastern Region sport manager Mark Inglis said the event had a proud history and this year twilight racing had been introduced on the Saturday night for beach events.
"It's an exciting new initiative. The intention is to speed up the large programme throughout the weekend and ultimately result in less conflict of events," he said.
Three clubs will travel from the South Island for the event - Dunedin's St Clair and Christchurch outfits South Brighton and North Beach.
Travelling furthest from the north are Red Beach and Orewa who have the largest contingents with 88 and 79 respectively. Hosts Mount Maunganui have the third largest group with 75 athletes followed by Auckland's Piha (72) and Mairangi Bay (54).
Events include beach sprint, beach flags, run swim run, surf race, board race, ski race, diamond race, ironman, 2km beach run, beach, board and ski relays, board rescue and taplin with the action beginning at 8am on Saturday.
Surf boats and canoes will also form part of the racing with more than 70 crews taking part in short and long-course races.