Phoenix Park is 5 times larger than Hyde Park, London.
Area: 1 km2 calculated
Hyde Park is one of the largest parks in London, and one of the Royal Parks of London, famous for its Speakers' Corner. The park was the site of the Great Exhibition of 1851, for which the Crystal Palace was designed by Joseph Paxton. Wikipedia
Area: 7 km2 calculated
Phoenix Park is an urban park in Dublin, Ireland, lying 2–4 km west of the city centre, north of the River Liffey. Its 11 km perimeter wall encloses 707 hectares, one of the largest walled city parks in Europe. Wikipedia