Submarius
Spearfishing conditions in Block Island
Legendary striped bass fishing, especially on the southwest side. Clear water for the Northeast, boulder structure, and deep channels.
Before you get in the water, open the app for the swell, wind, tide, water temperature, current and a visibility estimate for Block Island, RI.
Notable species
Block Island is known for:
Typical water visibility
Summer visibility around Block Island is commonly reported in the 10 to 30 ft range, a community guidance estimate, not a measurement. Rain, river discharge, swell mixing, and seasonality can shift real conditions dramatically day to day.
The app shows a model estimate of today's visibility here, with a confidence figure.
How the visibility estimate works →Clearest months at Block Island
Model climatology from the baked clarity ceiling: the typical day and the best case (90th percentile) visibility for each month, with a seasonal algae bloom proneness flag. These are labelled model estimates, not measurements.
| Month | Best case ft | Bloom risk |
|---|---|---|
| Jan | 13 | low |
| Feb | 14 | low |
| Mar | 14 | low |
| Apr | 14 | low |
| May | 15 | low |
| Jun | 15 | low |
| Jul | 15 | low |
| Aug | 19 | low |
| Sep | 17 | low |
| Oct | 14 | low |
| Nov | 13 | low |
| Dec | 13 | low |
Ceiling artifact global-reef-v10-obis-world; table baked Oct 15, 2026.
What Submarius shows for Block Island
This page reads Block Island at 41.17°N, 71.56°W, in New England. Open the same point in the app for:
- A 0 to 10 rating. For spearfishing at Block Island today, from Rough to Prime, and you can tap any factor to see why.
- Best 3 hour window. The three hours in the next 24 that score best.
- Tide. Rising, falling or slack, the next high or low, and a 24 hour curve.
- Wind. Speed and direction, with gusts.
- Waves and swell. Wave height and swell, with the second and third swell by the hour.
- Water temperature. With the air temperature underneath.
- Current. Drift in knots and the next slack, from a regional model, so it's offshore drift, not your entry.
- Visibility estimate. A model estimate with a confidence figure, not a measurement.
- Weather warnings. National Weather Service warnings for this spot and its marine zone.
- 8 day forecast (Pro). Days 2 to 8, hour by hour.
Block Island spearfishing map: reefs and wrecks
The reefs and wrecks layer in the app marks charted wrecks, reefs and obstructions around Block Island, where sources have them. Tap one for the seabed depth beside it (an estimate where no chart reports one), the least depth over the structure where a chart sounding exists, and today's conditions at that spot. The structures are merged from NOAA nautical charts and other public sources, so coverage is densest in US waters. It's a Pro map layer.
See the spearfishing map →Safety in the water
Every safety tool in Submarius is free. With Safety Watch you set a "back by" time and pick who watches. If you don't check in by then, the server alerts them by push or email, even if your phone is dead. It needs a free account and never contacts the coast guard.
In Spearfishing mode, a shark awareness card lists shark species recorded around Block Island (from OBIS records, for awareness, not live tracking) and community sightings from the last 48 hours, when the area has any. Signed in users can report a sighting, and app users within 25 km get a push.
Also at Block Island
More spearfishing locations
See all →Check Block Island before you head out
Today's conditions, safety tools and trip recording are free. Pro adds the 8 day forecast, the Pro map layers, cam playback and offline areas for $12.99 a month or $99 a year, or $149 once (US prices).