Blackpool’s Victoria Pier opened in 1893 and was renamed South Pier in 1930. The Grand Pavilion on the end of the pier was destroyed in a fire in 1964 and replaced a few months later by a new theatre. The new theatre was subsequently demolished in 1998 to make way for new white knuckle rides.
Today the promenade to the south of the pier is heavily built up with amusement arcades and the Sandcastle Water Park, although the grassed area (Flagstaff Gardens) seen in the photo is still there.
Although postally unused, we can make an educated guess that this postcard was published between 1902 (when divided backs were introduced) and 1918 (when the cost of sending a card rose from ½d to 1d).