The Bureau of Land Management Barstow Field Office has implemented a much more convenient way to purchase your Dumont Dunes pass. You can now go to Recreation.gov and get your pass online before you even head out for the season.  The fees will remain the same. There is a small service fee, but the total still comes to the same for the pass.   Purchase on Recreation.gov: https://www.recreation.gov/activitypass/e210305d-b769-11eb-87ed-16dbf55c498d   NOTE: Here is what you