What an incredible experience!
If you want to get up close and personal with dolphins and seals in the open sea then See All Dolphin Swims, Queenscliff is by far the best way to do it.
Around 30 drive minutes from Geelong, based at the Queenscliff Harbour you will start the day by bring provided with a wetsuit and all the snorkelling equipment you will need and jumping on board to professionally operated ferry for a day of fun. The guided tour then runs for around half a day and takes you from the harbour on board a ferry into the nearby sea to a number of areas perfect for sea life spotting and quality snorkelling. You can snorkel with the seals, swim alongside the dolphins, go snorkelling at a stunning reef, and if you're lucky the crew may just cook some freshly caught crab on board as a delicious snack. Then finish it all off with some fun jumping off the side of the boat before returning to the harbour.
If these stunning creatures are an interest to you, then this is definitely an experience not to be missed.