Southwold is part of the Suffolk Heritage Coast. A 101 foot tall white lighthouse constructed in 1890, is located within the town and is open to the public with tours to the top providing fantastic sea views. (lots of steep steps but it's worth it).
The renovated pier is the other main attraction on Southwold beach. It has several nice cafes and shops plus an 'Under the Pier' show, which despite it's name is on the pier not under it - anyway this has an amusing collection of handmade 'slot machines & simulator rides', these are NOT modern arcade machines, more like something from the 1920s -1930s

Overlooking the southern end of the beach is Gun Hill, which still has six eighteen pound canons looking out to sea. These date from the Elizabethan period, when they were used against the Dutch navy.
Like all of the seaside villages of Suffolk, Southwold is unspoiled by 'modern' amusement arcades and bingo halls. The whole town feels calm and somewhat peaceful.
More info here about the pier at
http://www.underthepier.com