There are two ways to thaw a turkey: cold water thawing or thawing in a refrigerator. The refrigerator method is more advisable as your turkey will last longer once defrosted (whereas turkey that is cold-watered thawed must be eaten right away). This method does take a lot of time though, so you’ll need to get started a few days in advance of when you want it to be ready to eat. You’ll need 24 hours of thawing time per 4-5 pounds of turkey, so a large 20 pound turkey will take about 5 days to properly thaw in the refrigerator.
If you opt for cold water thawing, it’s a lot faster but don’t forget that the turkey must be consumed immediately after it’s thawed, which isn’t always convenient! First, make sure your turkey is tightly wrapped in plastic with no tears or holes. Then fill your sink or a large bucket with cold tap water, submerge the wrapped turkey, and change the water every 30 minutes as it sits. How long it takes really depends on the size; USDA guidelines state that you should give 30 minutes of soak time for every pound of turkey.