Latics’ final away game of the season ended in defeat at Prenton Park.
Josh Hawkes and Kane Hemmings scored either side of half-time as John Sheridan’s much-changed side suffered another disappointing afternoon on the road.
With one eye no doubt on next season, Sheridan made five changes to the Latics team from the previous weekend, including starts for Harry Vaughan, Will Sutton and Jayson Leutwiler in goal.
Tranmere still have chance an outside of reaching the play-offs but the first half, for large parts, was nondescript.
Chances for Latics were scarce, Sutton heading over from a Jack Stobbs free-kick, while the winger also had a shot blocked by Peter Clarke after cutting in from the left.
Sam Hart also delivered a cross from the same flank to Davis Keillor-Dunn, only for but goalkeeper Joe Murphy to reach it first.
Josh Hawkes put Tranmere in front midway through the first half, sending a long-range shot into the bottom left-hand corner.
Hemmings should have given the home side the lead earlier but sent his shot straight at Leutwiler when clean through on goal.
The striker also missed a gilt-edged chance after half-time, clearing the crossbar with the goal gaping, receiving the loose ball when unattended in the area ftaer Kyle Jameson had done well with an initial challenge on Hawkes.
Hemmings did get his goal just after the hour, sending a decisive finish past the reach of Leutwiler.
Although Latics saw more of the ball as the second half progressed after three substitutions, clear chances were difficult to come by.
Jameson headed wide from a Nicky Admas, free-kick, while Callum Whelan had a chance and the closest the visitors came was when Stobbs drilled a low shot towards the bottom right corner, only to be denied by Murphy at full stretch.
Oldham Athletic: Leutwiler, Clarke, Hart, Keillor-Dunn, Jameson, Stobbs, Hunt (Whelan 54), Missilou (Adams 63), Luamba, Sutton, Vaughan (Hope 54).
Subs not used: Southerington, Couto, Hopcutt, Da Silva.
Tranmere Rovers: Murphy, Dacres-Cogley, MacDonald, Davies, Morris (McPake 71), Hemmings, Hawkes, Warrington, Nevitt, O’Connor, Clarke.
Subs not used: Doohan, Spearing, Colley, Foley, Maynard, Hayde.
Referee: Neil Hair