Hyde Park is a large park in London that appears as a location in both versions of Mario & Sonic at the London 2012 Olympic Games. In the Wii version, Hyde Park appears as the location for the Hyde Park Sticker Hunt!, Hyde Park Coin Collectors! and Guard the Hyde Park Diamonds! London Party minigames, as well as appearing on the mode's map as a landmark that can be passed through. In the Nintendo 3DS version, although not identified in game, areas of Hyde Park appear as the venues for the 10km Marathon Swim and Triathlon Events, as well as appearing as a location for several episodes in the Story Mode.
In the Nintendo 3DS version's Story Mode, Mario, Luigi, Toad and Omochao first notice the Phantasmal Fog over Hyde Park from the Main Stadium in Foggy Foes, and they head over to investigate, with Omochao remaining in the Main Stadium. The first episode that takes place in Hyde Park is Morning in Hyde Park, in which Daisy and Amy find the fog in Hyde Park and are attacked by some imposters it forms. After defeating the first few, they are attacked by several more. In Peach in a Pinch, Peach and Blaze protect several Toads from imposters, and after defeating them, find Daisy and Amy who explain what happened to them. The purple Toad tells the group that he had seen a suspicious figure around the park, and the group head off to investigate. In The Mysterious Thief, the group find Rouge in the park, and defeat her after she claims to be using the fog maliciously. Upon defeat, it is revealed that she was brainwashed by the Phantasmal Fog and reveals the location of the park's fog machine, which Blaze destroys, clearing the fog from the park. Mario, Luigi and Toad then arrive to help clear the fog, but after finding that it has already been cleared head to the British Museum while leaving the girls and Toads behind to protect the park. The group that remained at the park later call Mario, Luigi, Sonic and Tails in The Grand Showdown to tell them that they had cleared the park and encourage them to defeat Bowser and Dr. Eggman. In An Innocent Request, Peach, Amy, Blaze and the three Toads work on the invitations for the Olympic games in the park. They continue working on them in A Trick of the Wind, in which Daisy arrives, and after initially distracting Amy, she later joins the group to do the work. The group go for a walk in a different area of the park, during which a gust of wind blows some of the invitations into the lake. In The Real Beginning, Bowser and Dr. Eggman arrive at the park to collect their invitations, and after negotiating with Peach and Amy, the girls head off to find them for them. Bowser and Dr. Eggman manage to get their invitations from a pair of Toads, but mistake them for love letters and leave with them anyway. The group that were working on the invitations meet back up, and after finding that Bowser and Dr. Eggman have left, decide to head off too.