San Juan Islands & Anacortes Boater Snapshot, 2025
Where recreational boats spent their nights, who was visiting rather than home-ported, and how the Guemes Channel gateway moved through the season. Built from one year of public AIS positions run through Marina Intelligence geofences for 23 marinas, 17 anchorages and 17 channels.
Jan 1 – Dec 31, 2025 · NOAA AIS · 7.46M vessel-days processed
53vessels in Guemes Channel per day on average (139 on Jul 6)
2,620distinct vessels used Guemes Channel in 2025
5,917visitor boat-nights at Roche Harbor, the region's top transient draw
13,235boat-nights spent at anchor instead of in a marina
Visitor demand
Transient nights by month at the three biggest draws
A visitor night is a boat staying overnight somewhere other than its usual home, on a stay of 30 nights or fewer. Roche Harbor's peak is twice as steep as Cap Sante's, while Cap Sante holds visitors better in the shoulder months.
Roche HarborCap Sante (Anacortes)Friday Harbor
Market share
Visitor nights by marina, with an illustrative revenue estimate
Calibrated at Cap Sante, where the Port counted 16,015 guest nights in 2025 and AIS saw 4,043.
Assumption. Real rates vary by marina and season.
Marina
AIS visitor nights
AIS visitor boats
Avg length
Peak night
Est. all-boat nights
Est. revenue*
Shaded rows are the three biggest draws, shown in the chart above. *Estimated all-boat nights × average AIS boat length × the rate above. Cross-check: at these defaults Cap Sante comes to about $1.2M. The Port reported $1.3M of guest moorage on 19,952 nights in Nov 2020–Oct 2021, about $65 a night before later rate increases. That works out to $1.0–1.2M on 2025's 16,015 nights.
Leakage
Summer boats anchor out, and that's moorage nobody is paid for
All boat-nights at anchor by month. July alone is 3,712. Bars at right are visitor nights by anchorage.
Slip planning
Who visits Cap Sante, by boat length
40–49 ft boats are the core transient customer. 399 visitor nights came from boats 65 ft and over.
Guemes Channel traffic mix
Vessel-days in the channel by AIS type. Matches what the Guemes Channel live cam sees.
Method and limits
Source: NOAA public AIS for 2025, rolled up to one record per vessel per day. A ferry that crosses twenty times counts once a day.
Only boats with AIS transponders appear. Many small recreational boats carry none, so every count here is a floor. Camera counts on Guemes Channel can measure how big that gap is.
Visitor night: a pleasure or sailing boat's night at a marina or anchorage that is not its home (the place it spent the most nights in 2025), on a stay of 30 nights or fewer. Longer stays are treated as seasonal or monthly tenants, not visitors. Gaps of up to 3 days without AIS do not break a stay.
AIS coverage: 25% default, from Cap Sante 2025 (4,043 AIS visitor nights against the Port's 16,015 guest nights). Two other checks come in a little lower: 17% of recreational boats carried AIS in a peer-reviewed Danish coastal study, and AIS saw 1,229 Cap Sante visitor boats in 2025 against 7,388 guest vessels in the Port's 2020–21 study.
One coverage factor is applied to every boat size. Larger boats are more likely to carry AIS, so this overstates large-boat totals and revenue somewhat. Coverage by size will come from Port guest records and Guemes Channel camera counts.
Revenue figures are illustrative and use a single assumed rate.