RV National Parks Guide

Reservation window calculator: when to book your national park campsite

Choose the campground you want and the day you plan to arrive, and the calculator tells you the date your booking window opens and the time of day, in the zone the park publishes and converted to the park's own clock. It knows Recreation.gov's six-month rolling rule, the 14-day windows at Zion South and Bryce Sunset, Yosemite's five-months-ahead release on the 15th at 7 am Pacific, Acadia's first-of-the-month release, Furnace Creek's winter-only season, Rocky Mountain timed entry and the concession parks that run their own calendars. It is for anyone who has lost a summer site by logging in a day late.

Pick a campground and an arrival date.

Verified 2026-10-28, confirm before booking. Windows change by season and by site; the facility page linked in the result is the authority on the day.

How it works, how to use it, and what it does not cover

Each campground in the list is tied to one of a dozen booking rules we verified in October 2026. The common one is Recreation.gov's rolling window: a site becomes bookable exactly six months before the arrival date, so a July 15 arrival opens on January 15. If your arrival day does not exist six months earlier (August 31 has no February 31) the calculator moves to the last day of that month and tells you to confirm, because facilities handle that edge differently. Fourteen-day windows (Zion South, Bryce Sunset, Big Bend Cottonwood) are plain subtraction. Yosemite's Valley campgrounds use a block release: on the 15th of each month at 7 am Pacific, all dates from the 15th five months later to the following 14th go on sale together, so the calculator finds which block your date falls in. Acadia releases 90% of sites on the first of the month six months ahead at 10 am Eastern and the last 10% fourteen days out. Furnace Creek is only reservable for arrivals between October 15 and April 15, Canyonlands' Needles Loop B only mid-March to mid-November; outside those dates the tool says first-come instead of inventing a date.

Use the result like a calendar entry. The date is the morning to be logged in; the time shown first is the one the park or Recreation.gov publishes, and the second is the same instant on the park's clock, so a Grand Canyon booking at 10 am Eastern reads 8 am in Arizona, which does not observe daylight time. Where the time of day is not printed on an official page, which is true of the generic Recreation.gov window, the tool says so and you should be at the screen ten minutes early. Lines beneath the date list the second release batch, the next-evening permit drops for Rocky Mountain and Logan Pass, and whether the window is already open.

What it does not cover: lotteries (North Pines in Yosemite runs one alongside the five-month window), group sites, backcountry permits, state and private campgrounds, and the Everglades, Big Bend RV Park and Olympic Log Cabin concessions, which publish no advance window at all; for those the tool returns "unknown" with the operator's contact rather than a guess. Dates are 2026 rules applied forward: parks revise windows between seasons (Yellowstone's concession campgrounds move to Recreation.gov for 2027), and Recreation.gov facilities can switch a site between the six-month, two-week and four-day pools. The calculator also cannot see availability, only when availability begins, and it knows nothing about the 18-day booking-change lock some facilities apply. Treat the output as the time to be ready, and the source link as the final word.

Data last verified 2026-10-28. Prices, hours and rules change; confirm with the official source before you go.

Sources

Related guides

Frequently asked questions

What time do Recreation.gov campsites actually become available?

For most national park campgrounds, six months before the arrival date on a rolling daily basis. Recreation.gov does not print one release time on its policy page; the facility pages we read (Mather, Big Meadows, Black Rock, Cottonwood) say "up to 6 months in advance" without a clock time, and the widely observed release is 10:00 am Eastern. The calculator shows that time converted to the park's zone and labels it as unverified so you log in early. Parks that set their own clock are different and verified: Yosemite releases at 7 am Pacific, Acadia at 10 am Eastern on the first of the month, Rocky Mountain timed entry at 8 am Mountain.

Why does Yosemite give me a date on the 15th, not six months before my arrival?

Yosemite does not use a rolling window for its Valley campgrounds, Wawona and Hodgdon Meadow. On the 15th of each month at 7 am Pacific it releases a whole month of dates five months ahead: on February 15 everything from July 15 to August 14 goes on sale at once. So an arrival on July 10 opened on January 15, and July 20 on February 15. Tuolumne Meadows releases half its sites two months ahead the same way and half two weeks ahead; the smaller campgrounds release two weeks ahead, daily.

My date says "window already open". Is it too late?

It means the release date is in the past, which for popular summer dates usually means the site sold out months ago. It is not hopeless: cancellations are released back continuously (Recreation.gov charges a $10 fee, so people cancel), many parks hold a second batch for 14 days or 4 days before arrival (Acadia 10%, Shenandoah, Glacier's Apgar, Big Bend), and first-come loops exist at Needles, Mammoth in winter, Mathews Arm and Loft Mountain. Check at 10 am Eastern daily and again the evening before.

Yellowstone used to book through Xanterra. Which system does it use now?

For 2027 stays, Recreation.gov. The Yellowstone National Park Lodges pages read in October 2026 state that Fishing Bridge RV Park, Madison, Bridge Bay, Grant Village and Canyon move to Recreation.gov for 2027 with a roughly six-month window and individual site selection; the Recreation.gov-run campgrounds (Mammoth, Indian Creek, Lewis Lake, Slough Creek, Tower Fall) were already there. Grand Teton's campgrounds have been on Recreation.gov since 2022 with a six-month window; the Grand Teton Lodge Company says June 1 opens December 1.

Which bookings do RVers forget?

Three. Rocky Mountain timed entry (May 22 to October 12, 2026), released at 8 am Mountain on the first of the preceding month, is included with a campground reservation but not with a Longs Peak walk-up or a day trip. Glacier's Logan Pass shuttle tickets opened 60 days ahead in 2026, and matter because any rig over 21 ft cannot drive the alpine section itself. And Trailer Village at the Grand Canyon, the only full-hookup park on the South Rim, books 13 months ahead through Delaware North, not Recreation.gov, though it has been closed since August 31, 2026 under water restrictions.