A try from Waikato's captain Jackson Willison in the 76th minute sealed Bay of Plenty's relegation to the Championship for 2014.
Willison's try in Tauranga secured Waikato a 28-25 victory and it was the Steamers' second late loss, in as many matches, after they went down to a 80th minute Counties-Maukau penalty last weekend.
The five-pointer came after the Mooloo men attacked off a scrum on Bay of Plenty's five-metre line. The outside centre ran onto a pass from Sam Christie before burrowing his way over the line.
All Waikato's other points came via the boot of Trent Renata, who kicked seven penalties and a conversion. For Bay of Plenty, who led 15-12 at half-time, Josh Sole, Tino Nemani and Johan Bardoul scored tries. Willia Ripia added their other points via two penalties and two conversions.
For Bay of Plenty:
Tries: Sole, Bardoul, Nemani
Con: Ripia 2
Pens: Ripia 2
Pens: Renata 7
Bay of Plenty: 15 Elliott Hagen, 14 Tino Nemani, 13 Kendrick Lynn, 12 Sam Beard, 11 Kimami Sitauti, 10 Willie Ripia (c), 9 Josh Hall, 8 Carl Axtens, 7 Tanerau Latimer, 6 Johan Bardoul, 5 Josh Sole, 4 Culum Retallick, 3 Pingi Tala'a, 2 Nathan Harris, 1 Kane Hames.
Replacements: 16 Kalem Chan Boon, 17 Joe Royal, 18 Tim Bond, 19 Joe Tupe, 20 Beau Robinson, 21 Toma Te Aihe, 22 Nick Evemy.
Waikato: 15 Trent Renata, 14 Semisi Masirewa, 13 Jackson Willison (c), 12 Sam Christie, 11 Niko Malo, 10 Wharenui Hawera, 9 Brad Weber, 8 Adam Burn, 7 Zak Hohneck, 6 Rory Grice, 5 Whetu Douglas, 4 Brian Alainu'uese, 3 Ben Tameifuna, 2 Brayden Mitchell, 1 Toby Smith.
Replacements: 16 Vance Elliott, 17 Paul Alo-Emile, 18 Josh Tyrell, 19 Zane Kapeli, 20 Kylem O'Donnell, 21 Save Tokula/Joe Perawiti, 22 Falelima Siinei.
Referee: Ben O'Keeffe