The 2008 world champion completed 70 laps of the Sakhir circuit and ended the final day with a time just 0.02 off the best lap of the week set by Brazilian Felipe Massa for Williams on Saturday.
"This has definitely been the most challenging winter I've experienced and the car is still very much a work in progress," said Hamilton, whose team did more laps than any other over the 12 days of testing in Spain and Bahrain.
"But we've learnt a lot over the course of these last few weeks and overall it's been a good winter of testing for us."
Formula One has undergone the biggest technical revolution in more than 20 years, with the introduction of a new turbocharged V6 engine and energy recovery systems.
"There's so much to learn with these new cars; it's just mind-blowing and I don't think anybody can be fully ready for the challenge of this season," said Hamilton. "But I feel as ready as I can be and I'm looking forward to seeing where we are in Melbourne."
Williams were second fastest on Sunday but recorded more mileage than anyone else on the day, with Finland's Valtteri Bottas chalking up 108 laps.
Ferrari's Fernando Alonso was third and did 74 laps in a session that was extended by half an hour to allow teams to test under the floodlights which will be used for next month's night-time Bahrain Grand Prix.


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