Fill a large pot with 1-2 inches of water. Bring the water to a boil. Use enough water to fill the pot without the steamer basket touching the water.
While the water is coming to a boil, prepare the lobster tails. Use kitchen shears to carefully cut through the top shell of each lobster tail lengthwise, starting from the open end and stopping just before the tail fin.
Gently spread open the shell to expose the lobster meat. See notes above for detailed steps on how to butterfly the tail if preferred. Sprinkle Old Bay, salt, and pepper over the lobster meat.
Once the water is boiling, place a steamer basket or metal colander into the pot. Ensure that the bottom of the basket or colander does not touch the boiling water.
Arrange the prepared lobster tails in the steamer basket or colander, shell side down.
Cover the pot with a lid and let the lobster tails steam for about 6 to 8 minutes, depending on the size of the tails. The meat should be opaque and firm to the touch when cooked through. The shells will also turn a vibrant red color.
Carefully remove the steamer basket or colander from the pot, using oven mitts or tongs to protect your hands from the hot steam. Transfer the steamed lobster tails to a serving platter.
Drizzle in butter if preferred.