The pool had been closed for two months so the building could be strengthened to meet the earthquake provisions of the building code.
Free entry, a sausage sizzle, games, music and Queenstown Lakes District Council pool mascot Paddles helped mark the occasion.
QLDC health and fitness team leader Patrick Healy said there was a ''fantastic'' atmosphere at the pool throughout the day and great feedback from the public who attended.
''They're really happy and really grateful that we've got the pool back open for them. A lot of people have been missing their swimming.''
Mayor Vanessa van Uden recently thanked the Central Otago District Council for being a ''good neighbour'' and welcoming Wanaka swimmers to the Cromwell pool over the past two months.
QLDC will begin consultation with the Wanaka community next month over options for new swimming facilities.
The council will consider the options at an extraordinary council meeting on October 9, then invite ratepayers and residents in the Wanaka ward to give their views.
A decision on location, size, standards and timing of a new facility will be made in time for the project to be included in the 2015-25 10-year plan.
