Lough Tay, famously known as the "Guinness Lake" due to its dark waters and white sandy beach, is a stunning natural landmark in Ireland's Wicklow Mountains. Access is primarily by car to various roadside viewpoints along the R759, with free parking available, though direct access to the privately owned lake shore is restricted, making it less accessible for those with mobility issues beyond the viewpoints. Visitors can enjoy it solo as part of a scenic drive or via numerous guided tours of the Wicklow Mountains. While accessible year-round, the optimal time for clear views and milder weather is from spring to early autumn, as winter can bring fog and colder conditions. Viewing Lough Tay from public spots is free, with costs mainly comprising transportation (car rental, fuel, or tour fees). A typical stop at a viewpoint for photos and admiration lasts 15-30 minutes, though it often forms part of a longer half-day or full-day exploration of the Wicklow Mountains National Park. It's important to dress for changeable Irish weather, and remember that activities like swimming or boating on the lake are not permitted due to its private ownership.