Safari Park Kanchanaburi is an open zoo in Bo Phloi district, well north of Kanchanaburi town. Visitors come for drive-through animal encounters with giraffes, zebras, deer, and other large animals, and it is especially popular with Thai families and travellers who want a lighter day after the war cemeteries and railway museums.
Go with clear expectations. This is a commercial wildlife park rather than a conservation reserve, and the close-contact animal experiences will not suit every traveller. If you are comfortable with that, it can fill half a day, but it sits below Kanchanaburi's stronger historical sights and natural trips such as Erawan National Park.