Sunset Bay & Cape Arago Tide Pools 2026: Coos Bay's Best Low-Tide Days

The July and August 2026 dawn runs are now past. This guide preserves its original July 16 tide tables as dated history, including that day's −2.00 ft MLLW low at 8:22 AM at NOAA Charleston station 9432780. For upcoming predictions, use the current Charleston tide calendar, and plan around daylight, current site access and a safe return margin.

Updated October 10 for historical framing. Park-access and species notes below retain the original July 16 source snapshot; recheck the linked official park guidance before a trip. Tide-window intervals are predictions, not safe-access hours.

Charleston sits where Coos Bay meets the open Pacific, and the three state parks strung down Cape Arago Highway — Sunset Bay, Shore Acres, Cape Arago — hold two of Oregon's best tidepool grounds within about four miles of each other. The tide station at Charleston, NOAA 9432780, is the reference for all of it.

The original July 16 ranking for the rest of 2026

These are the original eight deepest daylight-qualifying windows remaining as of July 16, ranked by depth. They are preserved as a dated snapshot; several dates are now past. Daylight qualification means at least 30 minutes of the modeled window overlaps daylight, not that the low itself or the whole interval is in daylight.

Computed 2026-07-16 from NOAA station 9432780 predictions, MLLW.

Read the time column and the year's shape appears. Every deep summer low is a morning; every deep low from late October on is an evening. The deepest of them all, −2.05 ft on Christmas Eve, is nearly useless: its window opens at 4:10 PM and holds only about 36 minutes of light before a roughly 4:46 PM sunset (derived from the window's daylight minutes), with the low itself arriving long after dark. That is why the deepest tide in this original snapshot scores 59 while July 16's slightly shallower one scored 90 — the score is measuring usable water, not just depth. The methodology page shows the formula.

July 16 was a summer daylight pick in this original snapshot. It is now past, not a date to plan a new visit around.

Historical summer windows: July 16–18, then August 11–14

Original next-60-day snapshot, computed 2026-07-16 from NOAA station 9432780; these July/August dates are now past. Scores (0–100) weigh tide depth and daylight together.

The July run was the gentle tail of July's new-moon cycle: an 8:22 AM low on Thursday, drifting past 9:00 AM Friday and 9:45 AM Saturday as the depth faded. Saturday the 18th was the only weekend day in the table — a modest −0.66 ft at a mid-morning hour. These are historical comparisons, not upcoming visit recommendations.

The August 11–14 run was the final dawn series discussed in the original guide, and it rewarded the early alarm unevenly. Tuesday the 11th was deep (−1.65 ft) but its 5:49 AM low came about half an hour before sunrise — around 6:18 AM, derived from the window's daylight minutes — so it scored only 73. Wednesday the 12th, a slightly deeper low just after sunrise, was the pick of that run. If you are wondering why every deep summer low on this coast is an early one, the dawn-lows guide unpacks the mechanics; the Oregon coast minus-tide calendar puts Charleston beside Garibaldi, Newport, and Port Orford month by month.

Where to go: Sunset Bay, then South Cove

The two tidepool grounds bracket Shore Acres along the same stretch of Cape Arago Highway, and Oregon State Parks' own comparison is a fine itinerary. Per the Sunset Bay page: "Sunset Bay's protected shoreline provides easy access to intertidal areas, while Cape Arago, located about 4 miles farther down the highway, features the South Cove trail, which leads to a sandy beach and superior tidepools where you can observe a variety of intertidal plants and animals (please enjoy them with your eyes only)."

Sunset Bay is the easy start: a sheltered cove with a day-use area, and a campground with yurts that makes a dawn low painless. It is the forgiving option with kids or on a first visit — protected water, short walk, facilities close by.

Cape Arago's South Cove is the payoff. From the viewpoint parking at Cape Arago, the South Cove trail drops to a sandy beach and the reef the parks call "superior tidepools" — shelves that a −2 ft tide peels back a long way. It is a real descent (and climb back out), so budget for it. Two practical notes from the park's current advisories: the Cape Arago restroom building is closed ("Facilities open in Sunset Bay day-use or Shore Acres State Park"), and drones are prohibited in the park.

Parking, all three parks: Oregon State Parks is explicit — "Within the boundaries of Sunset Bay, Shore Acres, and Cape Arago State Parks, a parking permit is required anywhere you park, including designated parking lots, pullouts, and roadside areas within park boundaries." Day permits are sold on site, annual permits online. Shore Acres, the middle park, is open 8 a.m. to dusk; its formal garden and cliff-edge overlooks make it the natural between-tides stop, and a segment of the Oregon Coast Trail links all three parks if you would rather walk than drive.

Simpson Reef: the loudest overlook in Oregon

Just past Shore Acres, the Simpson Reef Overlook faces Shell Island and its surrounding reef — part of Oregon Islands National Wildlife Refuge, and, per the Friends of Shore Acres, "one of the few places on the Oregon coast where visitors can literally see thousands of marine mammals." Five species of pinnipeds haul out here — harbor seals, northern elephant seals, California and Steller sea lions among them. Bring binoculars.

Two access rules keep it that way. The refuge rocks and islands are closed to public access at all times — this is an overlook, not a destination. And Cape Arago's North Cove trail, which looks onto the reef, closes every year from March 1 to June 30 to protect seal pups; it reopened July 1, so mid-July visitors get both coves for the first time since winter. The parks' July event calendars also list guided wildlife-viewing sessions at Simpson Reef — check the Sunset Bay or Shore Acres event listings if you want a spotting scope and a ranger.

What you'll find in the pools

Charleston's recent community observations read like a sea-slug field guide. Of the ten most-reported intertidal animals within a few kilometers of the station in the last two months, eight are sea slugs: the Horned Nudibranch (Hermissenda crassicornis) leads the list, followed by the Monterey Dorid (Doris montereyensis), Red Sponge Dorid (Rostanga pulchra), Branched Dendronotid (Dendronotus venustus), White-and-orange-tipped Nudibranch (Antiopella fusca), Black and White Dorid (Acanthodoris rhodoceras), Odhner's Dorid (Doris odhneri), and Hedgpeth's Sapsucker (Elysia hedgpethi), a sap-sucking slug from a different lineage than the nudibranchs. The two non-slugs are workhorse snails: the Black Tegula (Tegula funebralis) and the Striped Dogwinkle (Nucella ostrina). Finds this small and this soft are what the deepest lows are for — the lower the water, the more of the shore you get to search.

Species reflect recent iNaturalist observations near the station (CC BY-NC, © the individual observers); NOAA is the tide-prediction data source. What you actually see depends on the day.

How to work the window

The historical summer table's arrive-by column subtracts an hour from the low; it is not a winter daylight or access plan. Allow enough time for the return walk to be off tidal rocks before dark or site closing, whichever is earlier, and skip a visit without enough daylight and safe access. The state parks' tidepooling guidance is short and worth quoting: "keep your eyes on the ocean and stay aware of changing tides, sneaker waves, and drift logs." On South Cove's shelves the returning tide can reach around behind you, so pick your exit line on the way out. And both parks repeat the same ethic — enjoy the animals with your eyes only.

One honesty note: station 9432780 sits at Charleston, inside the Coos Bay entrance rather than on the open shore. Its predictions are the standard reference for Sunset Bay and Cape Arago, but the exact minute of low water on an open-coast shelf a few miles away can differ a little. These are predictions, not observations; check conditions before you commit to a scramble.

After the morning season ends

From September on, Charleston's daylight windows thin fast, and the deep water moves to the far end of the day: −1.75 ft at 5:54 PM on November 24, −1.90 ft at 5:42 PM on December 23 — with roughly an hour to an hour and a half of usable light on the falling tide before sunset. Those dusk lows ride the same alignments as king tide season, when the winter's highest highs drain to the year's lowest lows a few hours later. These original dusk comparisons do not make the after-dark lows suitable visit times; plan any visit within daylight and current access limits. The summer morning runs above are now history.

For upcoming dates, the current Charleston calendar and October calendar carry current predictions. The year heatmap shows the seasonal pattern, the trip picker finds multi-day runs, and the August calendar remains an archive of the dawn season.