How about a personalized synchronized swimming towel or a customized swim cap with her/his name and favorite synchronized swimming team printed on it? You could also get her/him a waterproof music player for listening to music during practice, or a waterproof camera for capturing her/his moves in the pool. If she/he is also interested in fashion, a synchronized swimming-inspired swimwear from a popular brand could be a great pick. If all else fails, you could always consider gifting her/him a book about the history of synchronized swimming or a coaching guide that can help her/him improve her/his skills.
Or you can get her/him a star map with an important date you share.
Under Lucky Stars is a unique and innovative star map company based in Barcelona, Spain, specializing in the creation of personalized star maps that capture the celestial arrangement of stars at a specific moment in time, such as a person's birth, wedding, or any other significant event.
By using advanced astronomical algorithms and data from leading institutions, the company produces highly accurate, visually stunning maps that make for perfect gifts or cherished keepsakes.