There are seagoing versions of Johnny Rockets on several of the larger Royal Caribbean ships. However, Johnny Rockets is only open for breakfast on Allure and sister ship Oasis of the Seas. Furthermore, while there is a cover charge if you visit Johnny Rockets for lunch or dinner, breakfast is complimentary.

On the Allure of the Seas, Johnny Rockets is complimentary for breakfast, but it carries an additional fee for lunch and dinner. The free breakfast usually consists of classic American diner fare like eggs, hash browns, pancakes, and breakfast sandwiches, and it is a "hidden gem" because it is often much quieter than the Windjammer buffet. However, once the clock strikes lunchtime, the restaurant switches to its signature burgers, shakes, and fries, and a flat cover charge (typically around $12–$15 per person) applies. This cover charge includes your food and "The Original Shakes" or other beverages are usually an extra cost unless you have a beverage package. For those with a Royal Caribbean dining package, Johnny Rockets lunch and dinner are often included, though you should always check the specific terms of your package once onboard.