Leading the field with a time of 1:16.084, Hamilton was able to narrowly edge-out the Red Bull of Max Verstappen and Ferrari of Sebastian Vettel in a very close session, his two rivals behind by only 0.013 seconds and 0.082 seconds respectively.
Further adrift but also in the running were P4 Valtteri Bottas and P5 Charles Leclerc, the latter 0.308 seconds behind the leader.
A session of completely dry running after a wet FP2 on Friday, conditions were still not ideal for the drivers due to an oil spill in sector two caused by the preceding Formula 2 race.
Unable to run for the first ten minutes while marshals placed cement dust on the track, the subsequent clouds of white smoke made visibility and grip in less-than-ideal for most of the session, with all drivers needing a late charge to get the most from the session.
That said, the cement dust didn’t stop the track record (for a race-weekend) from falling, first being snatched by the Red Bull of Verstappen, and ultimately ending up in the hands of Hamilton, who now heads into qualifying having topped both dry sessions so far this weekend.
From a disappointing showing last Sunday in Germany, the Briton looks back to his best in Hungary, albeit with a serious fight on his hands if this session is any indication.
Further afield, Pierre Gasly was P6, exactly six-tenths off the best time, and just as notably, 0.587 seconds off his teammate.
Lando Norris was best-of-the rest for McLaren with a 1:16.774 — the last of the runners to be within a second of Hamilton — with Kimi Raikkonen (8th), Carlos Sainz (9th) and Kevin Magnussen (10th) all further adrift from the Mercedes.