Kayaking Tomales Bay in search of bioluminescence
Tomales Bay is one of the best places in California to kayak through bioluminescent plankton, but you can only see it if three things align: it has to be dark enough (moon below the horizon), late enough (after full darkness), and the right season (late spring through fall when dinoflagellate populations peak). What follows is a trip report followed by some planning tools for your own trip.
The First Trip — September 23–24, 2022
We reserved Boat Site B at Point Reyes National Seashore Campground, a group site on the west shore of Tomales Bay at Marshall Beach, accessible only by water.
The original plan was to park overnight at, and launch from, Miller Boat Launch on the east shore and paddle across to camp.
Straight-line, the route is about 1.78 miles.
By timing the crossing for slack tide, though, we could have cut straight across the Bay — only about 4,500 feet — and then head southeast along the shore to the camp site. This would have minimized exposure to open water risks.
But, in planning this, I chickened out a bit. The group included people with variable kayaking experience and high afternoon winds can lead to large waves on the Bay, so we instead launched from Chicken Ranch Beach to the south, and paddled 5.29 miles along the shore so that there'd be an easy way to bail if things went wrong. This choice brought us into Type II Fun territory.
I chose the date to maximize darkness. Moonset on September 23 was at 6:19 PM — well before sunset — leaving the whole evening dark. (The planner below includes all this information in an easy-to-use form.)
In addition, civil twilight ended at 7:39 PM, nautical twilight at 8:06 PM, and astronomical twilight at 8:33 PM.
Winds pick up in the afternoons so launching before noon is recommended and, in fact, local outfitters won't rent kayaks after noon even though winds tend to drop off again later in the day. Given the tide and light, starting around 4:00 PM during slack tide should have given enough time to paddle and set up camp before dark.
However, due to folks' work schedules, we weren't able to get onto the water until 5:12 PM (a vanguard from our group acquired the kayaks). This meant meant fighting the incoming tide that started at 5:53 PM on the 23rd. But not just the tide! Also that wind. The result was a brutal, soaking paddle. We got to camp at 7:17 PM, so the trip took about two hours.
On the way out we didn't time it much better and got on the water at 11:25 AM to fight the outgoing tide on our way back. The winds were calm and the paddling was much easier than the day before. We took it slow and arrived at 1:18 PM, so the trip took about two hours.
Most beaches on the west shore are tidally dependent and will disappear at tides above 5 ft. Since September 23 had a high tide of 5.28 ft at 11:11 PM, we needed to set up camp well above the waterline.
Cold and wet, some members of the trip retreated to tents immediately to get warm and no one was up for venturing back out again into the dark. The fabled bioluminescence didn't show itself in the bay near our tents.
But the weekend wasn't a wash. Our visit corresponded with the annual campout of the Traditional Small Craft Association. They played folk music by their fire well into the night.
The next morning we went hiking up and around our mini-bay.
It took a while, so we investigated climbing across the cliffs to get back to camp.
But were spared that adventure by the TCSA coming over in one of their boats!
The Second Trip — October 6–7, 2023
I returned a year later with a friend to try again. Blue Waters normally rents sit-on-top kayaks, but as a former kayak guide I was able to get a lighter enclosed double. This time we used the Miller Boat Launch. The winds were, by luck, exceptionally calm when we got on the water at 3:30 PM. By 4:39 PM we'd successfully crossed to the opposite shore and were making our way along it and by 5:47 PM we had our tent set up at Tomales Beach (which is closer to Miller than Marshall Beach).
After dark, we got back on the water and kayaked from Tomales Beach up to White Gulch Beach - which is in a deep bay directly west of Hog Island. We found bioluminescence the whole way, and it was incredible. Every paddle stroke lit up the waters and disturbed kelp shot lightning bolts away from us.
Planning
See also the NPS Plan Your Visit site.
Kayak Rentals
Blue Waters Kayaking at Point Reyes Station rents double kayaks overnight for $198 (500 lb weight limit), which works out to about $100 per person.
What to Bring
Beyond standard camping gear, this trip requires a few items you might not already own or which are particularly important:
- Portable toilet — required unless you camp at Marshall or Tomales Beach (vault toilets provided). A Cleanwaste GO anywhere kit (wag bag) or similar works well.
- Dry bags — all gear goes in the water to get to camp. Everything must be waterproofed. Blue Waters rents these in sizes up to 50 gallons.
- Bilge pump and paddle float — required for the open-water crossing; a paddle float enables self-rescue if you capsize. Blue Waters probably has these.
- Kayak navigation lights — legally required when paddling at night. A white stern light and bow light visible from 360° are the minimum. Or just wear headlamps!
- Red headlamp — white light kills your night vision and ruins bioluminescence viewing. Switch to red mode once it's dark.
- Offline maps and GPS points for campsites. — the GPS points are helpful for finding your way to the campsite, especially after dark!
- Recreation.gov permit printout — must be displayed on the dashboard of every vehicle at Miller Boat Launch for overnight parking.
- Coloured light to leave on beach — when finding your way back at night it'll be helpful to leave a light on the beach. If it's coloured or you have more than one that'll help you identify it as your beach.
- Fresh water — there's no where you can get this after you leave civilization. Bring a good supply.
- Firewood — scavenging goes against minimal-impact principles and you'll also end up with a smaller, smokier fire.
- Sunscreen — There is no shade on the water.
- Sunglasses — There is no shade on the water.
Launch points
Three launch points have overnight parking for boat-in campers:
| Launch | Phone | Lat | Lon | Notes |
|---|---|---|---|---|
| Miller Boat Launch | 415-499-6387 | 38.2000 | -122.9215 | East shore, Hwy 1 north of Nick's Cove. Cement ramp, pier, restrooms. Overnight parking in upper lot; display Recreation.gov confirmation on dashboard. No camping or beach fires. |
| Tomales Bay Resort | 415-669-1389 | 38.1071 | -122.8629 | West shore, 0.9 mi north of Inverness. Only west-shore overnight parking option. Fee required. |
| Lawson's Landing | 707-878-2443 | 38.2322 | -122.9683 | Dillon Beach, north end of bay. Sand-bottomed ramp; forklift or 4WD launch. Dump station, boat rentals, restrooms. Day-use fee; overnight parking requires purchasing a campsite. |
Tomales Bay Resort is by Chicken Ranch Beach (38.109940, -122.865088) and I believe in 2022 we were able to leave our cars parked by the roadside there for free. Lawson's Landing does not look like a good place to launch from - it's outside the mouth of the Bay where you'll be encountering the ocean directly.
Where to camp
(click image for PDF)
Permit-required boat-in campsites, south to north:
| Beach | Lat | Lon | Notes |
|---|---|---|---|
| Kilkenny Beach | 38.1456 | -122.9037 | |
| Long Cove Beach | 38.1521 | -122.9108 | |
| Marshall Beach | 38.1631 | -122.9155 | West shore, due west of Hog Island Oyster Co. Vault toilets. |
| No Name Beach | 38.1692 | -122.9214 | |
| Tomales Beach | 38.1739 | -122.9236 | Long sandy beach. Vault toilets. |
| Elk Fence South Beach | 38.1763 | -122.9269 | |
| Elk Fence North Beach | 38.1808 | -122.9305 | |
| Pelican North Beach | 38.1889 | -122.9367 | |
| Wall Beach | 38.1924 | -122.9413 | |
| White Gulch Beach | 38.1935 | -122.9465 | |
| Pita Beach | 38.2030 | -122.9503 | |
| Jacks Beach | 38.2098 | -122.9599 | Closed to camping since March 2018. |
| Blue Gum Beach | 38.2264 | -122.9770 | Strong tides and currents. |
| Avalis Beach | 38.2303 | -122.9807 | Closed to boats and camping since May 2023. |
| Duck Beach | 38.2351 | -122.9850 | Closed to boats and camping since May 2023. |
If you do not have a portable toilet, you are required to camp at Marshall or Tomales Beach, where there are vault toilets that you will need to use.
Distances and paddle times
Estimated distances and times from each launch point. Miller direct is the straight open-water line; Miller via shore crosses to the west shore at a waypoint near Pelican North Beach (38.190°N, 122.935°W), then follows the shore. Times calibrated at 2.65 mph (user's group: Chicken Ranch Beach → Marshall Beach in 2 hours over 5.29 miles). Actual time depends on fitness, current, and wind.
| Campsite | Miller direct | Miller via shore | Chicken Ranch Beach |
|---|---|---|---|
| Kilkenny Beach | 3.9 mi / 1:28 | 5.0 mi / 1:53 | 3.8 mi / 1:26 |
| Long Cove Beach | 3.4 mi / 1:16 | 4.3 mi / 1:39 | 4.4 mi / 1:40 |
| Marshall Beach | 2.6 mi / 0:58 | 3.5 mi / 1:19 | 5.3 mi / 2:00 |
| No Name Beach | 2.1 mi / 0:48 | 2.9 mi / 1:06 | 5.9 mi / 2:13 |
| Tomales Beach | 1.8 mi / 0:41 | 2.5 mi / 0:57 | 6.2 mi / 2:22 |
| Elk Fence South Beach | 1.7 mi / 0:38 | 2.3 mi / 0:51 | 6.5 mi / 2:28 |
| Elk Fence North Beach | 1.4 mi / 0:32 | 1.9 mi / 0:42 | 6.9 mi / 2:37 |
| Pelican North Beach | 1.1 mi / 0:26 | 1.1 mi / 0:26 | 7.6 mi / 2:53 |
| Wall Beach | 1.2 mi / 0:27 | 1.4 mi / 0:32 | 8.2 mi / 3:06 |
| White Gulch Beach | 1.4 mi / 0:32 | 1.7 mi / 0:40 | 8.5 mi / 3:13 |
| Pita Beach | 1.6 mi / 0:36 | 2.5 mi / 0:57 | 9.3 mi / 3:30 |
| Jacks Beach ⚠ | 2.2 mi / 0:50 | 3.3 mi / 1:14 | 10.0 mi / 3:48 |
| Blue Gum Beach | 3.5 mi / 1:20 | 4.9 mi / 1:50 | 11.6 mi / 4:24 |
| Avalis Beach ⚠ | 3.8 mi / 1:27 | 5.2 mi / 1:59 | 12.0 mi / 4:32 |
| Duck Beach ⚠ | 4.2 mi / 1:36 | 5.7 mi / 2:09 | 12.5 mi / 4:42 |
⚠ closed to camping. Generation script: github.com/r-barnes/tomales-biolum.
Wind
Afternoon winds can make the crossing difficult — kayak outfitters on the bay typically cut off rentals at noon. The table below shows average wind speed (mph) by month and time of day, measured at NOAA's Point Reyes coastal station, about 10 miles south of the bay on the outer Point Reyes Peninsula, 2010–2019. Winds in the bay itself may be somewhat lower due to surrounding terrain. On the two trips I've taken, the 9PM and midnight times are definitely too high - Tomales Bay was almost still on both occasions.
| Month | 9 AM | Noon | 3 PM | 6 PM | 9 PM | Midnight |
|---|---|---|---|---|---|---|
| Jan | 7.5 | 8.5 | 10.1 | 9.7 | 8.4 | 8.1 |
| Feb | 9.4 | 11.2 | 13.1 | 12.6 | 11.6 | 11.1 |
| Mar | 9.6 | 10.5 | 12.0 | 12.4 | 11.6 | 11.4 |
| Apr | 11.5 | 12.9 | 15.3 | 15.9 | 14.6 | 13.6 |
| May | 13.3 | 13.8 | 16.3 | 17.1 | 16.2 | 15.5 |
| Jun | 13.7 | 14.9 | 16.2 | 17.5 | 16.7 | 15.5 |
| Jul | 9.2 | 9.8 | 11.1 | 12.0 | 10.9 | 10.5 |
| Aug | 8.1 | 8.6 | 10.9 | 12.4 | 11.2 | 10.3 |
| Sep | 8.4 | 9.5 | 12.5 | 13.2 | 12.3 | 10.7 |
| Oct | 7.3 | 9.0 | 12.1 | 12.2 | 11.0 | 10.0 |
| Nov | 7.7 | 9.7 | 11.5 | 10.8 | 9.6 | 8.8 |
| Dec | 8.4 | 9.4 | 10.7 | 10.3 | 9.1 | 8.7 |
The bioluminescence planner below shows these averages for each month as a reminder.
For current conditions and forecasts:
- NWS Point Reyes forecast
- Windfinder Tomales Bay
- Windy.com
- NWS marine forecast (PZZ545)
- NWS Coastal North Bay marine zone
Data source and station search notes
The table uses NOAA NDBC station PRYC1 (37.996°N 122.977°W), a land-based C-MAN station on the outer Point Reyes Peninsula, averaging 2010–2019 top-of-hour UTC observations converted to Pacific time. The station's wind anemometer stopped reporting in 2020.
No comparable replacement was found: NDBC buoy 46013 (Bodega Bay offshore) reads ~30% higher due to open-ocean exposure; the WRCC Pt. Reyes RCA field station (38.094°N 122.950°W) covers 2006–present but historical data requires a paid access code (wrcc@dri.edu). Personal weather stations at Inverness (KCAINVER2, KCAINVER14) and Olema (KCAOLEMA3) are all offline with no archived data. NCEI's ISD history file contains no stations for Inverness, Olema, or Point Reyes Station town. Analysis code and raw data: github.com/r-barnes/tomales-biolum.
When is there bioluminescence?
Nights with calm waters and little wind are probably best.
Local guides say the following:
- August through November, coinciding with neap tides (link)
- June through mid-October (link)
- "Bioluminescence tends to be strongest in the summer and fall, although in recent years it has been seen regularly throughout the spring as well." (link)
But why settle for anecdata from guiding companies in the area (/s!) when we can do Science to this? The plots below draw on three monitoring datasets and have seasonal shading: green = spring (Mar–May), yellow = summer (Jun–Aug), orange = fall (Sep–Nov), blue = winter (Dec–Feb).
Species in the data
The monitoring programs track harmful algal bloom (HAB) species. Here's who's who and what they mean for bioluminescence:
- Lingulodinium polyedra ✨ — the bioluminescent dinoflagellate responsible for California's famous glowing red tides. When mechanically disturbed at night (by a paddle, a wave, a fish), it emits brilliant blue flashes. High cell counts strongly predict visible bioluminescence; the data show it rarely blooms in Tomales Bay or at nearby Bodega Bay. Given the excellent bioluminescence I saw in October 2023, it either has a separate population in the Bay that doesn't track with collected data or Tomales Bay glows with something else.
- Noctiluca scintillans ✨ — another bioluminescent organism (technically a non-photosynthetic dinoflagellate) that can produce green daytime blooms and blue nighttime glow. Not tracked by CalHABMAP; iNaturalist observations within 100 km of Tomales Bay are sparse and mostly from San Francisco. California has a mutant population that doesn't glow.
- Akashiwo sanguinea — a non-bioluminescent raphidophyte that dominates fall blooms in Tomales Bay. Forms brown/rust-colored surface scums; can cause fish kills through gill damage and oxygen depletion, but produces no toxins and no glow.
- Alexandrium spp. — dinoflagellates that produce saxitoxins causing paralytic shellfish poisoning (PSP). Not bioluminescent. Their presence drives routine shellfish harvesting closures in Tomales Bay.
- Dinophysis spp. — dinoflagellates that produce okadaic acid, causing diarrhetic shellfish poisoning (DSP). Not bioluminescent.
- Pseudo-nitzschia (two size groups) — diatoms that produce domoic acid, causing amnesic shellfish poisoning (ASP). Not bioluminescent; responsible for periodic closure of Dungeness crab fisheries along the California coast.
Though not all the species above have bioluminescence and the bioluminescent ones are absent from the data, some bioluminescent species are predatory. Noctiluca scintillans, for instance, is heterotrophic (no photosynthesis) and feeds on phytoplankton: diatoms, dinoflagellates, fish eggs. The large Akashiwo sanguinea fall blooms visible in the data could plausibly support Noctiluca populations, meaning those non-glowing blooms might indirectly predict bioluminescence from Noctiluca even when Lingulodinium is absent. Lingulodinium is primarily autotrophic (photosynthetic) so it can't feed on these other blooms, but might benefit from the same conditions which cause them.
Tomales Bay — temperature and chlorophyll
The CeNCOOS / UC Davis Tomales Bay buoy ran south of Hog Island (near where I saw bioluminescence) from 2019 to 2021 at hourly resolution. Chlorophyll blooms peak in spring and early summer; water temperature peaks in August.
Tomales Bay — HAB species
The CalHABMAP mid-channel buoy (same location, weekly samples) has run since 2021. Akashiwo sanguinea dominates the fall blooms; Lingulodinium polyedra — the bioluminescent species — is rarely detected.
Bodega Marine Lab — regional HAB context
The nearest CalHABMAP shore station is at Bodega Bay, just north of Tomales Bay in the same coastal upwelling regime. Weekly data since 2020 covers a fuller species list.
Raw data and plotting code: github.com/r-barnes/tomales-biolum.
Is it dark enough? Bioluminescence Night Planner
The planner below shows every night when the moon has set by 9 PM (so you'll be awake and have time to explore), or lunar illumination is <5%. The dark window runs from 1 hour after civil twilight until moonrise or civil dawn, whichever comes first. Times shown are shown in Pacific time. The values are calculated for Marshall Beach (38.163°N, 122.916°W), but that's a reasonable proxy for all of Tomales Bay. This ignores topography, so the sun and the moon will actually rise a bit later and set a bit earlier.
Check Show tides to overlay the day's high and low water times and heights. Tides matter for two reasons: most west-shore beaches disappear above 5 ft (bold entries), so you need enough beach above the waterline to camp; and tidal currents can make the Bay crossing harder away from slack water near a high or low. Tide predictions use harmonic constituents for San Francisco (NOAA 9414290) adjusted with the time and height offsets for Blake Landing (NOAA 9415396), the nearest NOAA subordinate station to the Marshall Beach. Predictions were spot-checked against NOAA's published tide tables for dates across 2026–2029 and agree within ±10 minutes and ±0.15 ft.