Yes, you can absolutely wear flip-flops on a Carnival cruise in 2026, and they are the "Gold Standard" for a "Pura Vida" day at the pool or on the Lido deck. During the day, flip-flops are the most supportive and "Bujan" choice for walking around the ship's outdoor areas. However, a grounded reality for 2026 is that Carnival maintains a "Cruise Casual" dress code for most evenings in the Main Dining Room and the specialty restaurants. While "High-Fidelity" flip-flops are usually tolerated during a "Casual" night, they are a "hard-fail" for the "Cruise Elegant" (Formal) nights, where guests are expected to wear more supportive footwear like dress shoes, loafers, or at least "Gezellig" sandals. To be supportive of your own safety: never wear flip-flops in the gym or during "High-Fidelity" physical activities like the SkyRide or ropes course, as you will be denied entry for a "hard-fail" on safety gear. For a supportive and frictionless vacation, pack one pair of "Pura Vida" rubber flip-flops for the beach and one pair of more supportive, "Gold Standard" leather sandals for the evenings.