At stumps the challengers were 115/5, on a day when 15 wickets were taken on a pitch that was slated as favouring the batsmen.
Bay of Plenty resumed on day 2 with Jono Boult the shining light, falling just six runs short of his century when he was caught out but his contribution had turned the momentum of the match.
Campbell Thomas, better known as a bowler, posted 45 runs batting at nine, while opener Tom MacRury reached 40 before being dismissed.
Keeper Tim Clarke, who has had a sterling season with the bat, took his season total to just shy of 300 runs with a gritty 26 as the Bay of Plenty side were bowled out for 318 late on day two.
Hawke's Bay resumed their second turn at bat at 84/2 on day three and went on the attack in their attempt to grab a defendable second-innings lead. Led by New Zealand under-19 batsmen Graeme Tryon, who blazed away to smash 143 off 159 balls, Hawke's Bay declared in their second turn at bat at 361/5, to set Bay of Plenty a target of 205 for outright victory.
The visitors lost two cheap wickets to be 17/2, with the third wicket falling at the 55-run mark.
Batting at four, Ben Musgrave took Bay of Plenty to victory with a commanding knock before he was caught behind for 102. Posting his maiden Bay of Plenty century, Musgrave hit 15 boundaries.
A 148-run partnership between Musgrave and Northern Knight Brett Hampton, who was there at the end with an unbeaten 63, gave Bay of Plenty the cup, which will spend the winter at Bay of Plenty Cricket HQ at the Bay Oval, Mount Maunganui.
Scoreboard:
* Hawke Cup challenge
* Hawke's Bay 162 (Indika Senarathne 33, GS Pretorious 32; Jono Boult 3/5, Brett Hampton 3/41, Tommy Clout 3/69) & 361/5 (Graeme Tryon 143, R Young 52; Jono Boult 2/99), Bay of Plenty 318 (Jono Boult 94, Campbell Thomas 45, Tom MacRury 40, Tim Clarke 26; BP Stoyonoff 3/52, L Dudding 3/54) & 209/4 (Ben Musgrave 102, Brett Hampton 63no, Joe Carter 28)