Do you have to boil octopus tentacles before grilling? One of the most popular methods is boiling, which can take anywhere from 20 to 45 minutes, depending on the size and thickness of the octopus tentacles. Octopus is delicious seafood that can be cooked in a variety of ways. It takes about 45 minutes to cook octopus tentacles. We recommend rice or pasta, but feel free to get creative! How long does it take to cook octopus tentacles? Bring to a boil over high heat, then reduce the heat to medium and simmer for about 45 minutes, or until the octopus is cooked through.Ĥ. In a large pot or casserole dish, combine the octopus, lemon, bay leaves, garlic, olive oil and salt and pepper to taste.ģ. If you are not comfortable doing this, ask your fishmonger to do it for you.Ģ. Start by cutting the octopus into small pieces.