The London 2012 hockey player's medal was taken along with her Team GB jacket at Mahiki Nightclub in London in the early hours of Wednesday, prompting a high-profile appeal for its return on Twitter.
The medal was posted anonymously to the England Hockey head office at Bisham Abbey on Friday but her jacket has not yet been recovered.
Olympic rower Alex Partridge, 31, from Henley, also had his bronze medal and Team GB jacket stolen at the same time and although the jacket was handed into a police station in north-west London on Thursday, his medal is still missing.
Hannah, 28, said: "I'm extremely pleased to have been reunited with my medal. It’s a huge relief. I’m enormously grateful to the Metropolitan Police and in particular to DCI James Harman who has kept me informed of their investigation throughout.
"I am indebted to everyone who has tweeted about it, everyone who has got in touch and who has publicised the situation. I can't thank you enough. I think all of you played a part in encouraging whoever had my medal to return it.
"Given the huge impact the Olympic Games has had on London and the UK I always held hope that it would be returned but it's still incredible to know now I have my medal back. People understand how much these medals mean to the athletes and those in the communities who have played their part in supporting us.
"I’m conscious that the police investigation is still ongoing and that Alex Partridge’s medal is yet to be returned and I urge whoever has it to return it too.
"Once again, I’d like to thank everyone who has played a part."
A 31-year-old man was arrested on Thursday and bailed pending further investigation.
Police confirmed they are retaining Hannah's medal as part of their inquiries but would return it to her shortly.
DCI James Harman of Westminster CID said: "We are still looking to recover the second medal, and we stress that our inquiries remain active.
"Our appeals for information stand and I take this opportunity to reiterate them - if the public can help we ask them to do so.
"Alex's medal has yet to be traced, and he is understandably keen to be reunited with it as soon as possible."
Call 0207 3217650 or Crimestoppers on 0800 555111 with information.
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