Byeongari Teukgongdae

Na Yeong-Gwang, a 13-month-old Hanbit swimming ace, tries to win her crush's heart by competing in a swimming competition. But the problem is that it's a team competition! The four unique babies are a fantastic cacophony of personalities, swimming with second-rate bodies that can barely hold it together! They'll have to use the strength they've gained from milk, or rather, their breastfeeding strength, to win!

(Source: Manhwakyung, translated)