How long does a deep sea fishing license last?

It depends on where you get the license.

In Florida, a resident can get a 1 year, a 5 year, or a lifetime Saltwater Fishing license. Nonresidents can get an annual (1 year), a 3 day, or a 7 day Saltwater Fishing License.

In California, residents and nonresidents can get a 1 year, 1 day, or 2 day Sport Fishing license. Nonresidents can also get a 10 day Sport Fishing license. Residents can get a lifetime Fishing License.