Personalized Submarine 3rd Birthday Toddler Long Sleeve T-Shirt. THINGS ARE LOOKING UP 3rd birthday Toddler Long Sleeve Tee - White with big number 3, colorful submarine, little deep sea explorer in the porthole and bright fish with bubbles. A classic for Fall, Winter and Spring, these long sleeve toddler t-shirts are sure to be a staple in your child's wardrobe. Whether layered or alone, this t-shirt is soft yet durable enough to stand up to your toddler's playtime demands.