When boiling lobster tails, the colour and texture serve as key indicators of doneness. A well-cooked tail will transition from a translucent grey to a vibrant red or bright pink. The meat should appear slightly opaque and firm yet tender to the touch. If the tail maintains a glossy, translucent appearance, that signifies it needs more cooking time.

Another effective technique involves checking the internal temperature with a meat thermometer. The optimal temperature for lobster tails is around 60-65°C. If you do not possess a thermometer, you can also slice into the thickest part of the tail. The flesh should be opaque and no longer shiny, indicating that it has reached the desired level of doneness.