There are several synonyms for the phrase "good fun". One option is "enjoyable", which implies that an activity is pleasurable and entertaining. Another synonym is "delightful", which suggests that something is charming, enjoyable, or enjoyable to experience. "Amusing" is another excellent option, indicating that something causes us to laugh or feel amused. "Entertaining" is another ideal option, suggesting that something is enjoyable, interesting, and gets us entertained in some way. Other synonyms include "merry', "festive", and "jovial". All these synonyms have different connotations and shades of meaning, but they all indicate that an experience is enjoyable and provides a sense of amusement or entertainment.