The recommended time to make a reservation for a student flat in Portsmouth is about 6 months in advance. For example, students for the September intake look for student housing in Portsmouth from March to May. First-year and international students may start looking for Portsmouth student accommodation in January. The time can vary depending on the specific accommodation provider and the demand in the area, but it is generally advisable to start looking and booking as early as possible to secure your ideal room. You can also take advantage of excellent deals and enjoy lower rental rates by booking early.