Hap's Reef
Dive site · Guam
Is it worth the trip?
90Good out of 100 for your dates
Best on Sat 7: Sea 0.5 m, Visibility over 30 m, Water 30 °C
Tue 3 · 89 out of 100
- Sea
- 0.6 m
- Wind
- 10 kn
- Gusts
- 14kn
- Air
- 30°C
Wed 4 · 90 out of 100
- Sea
- 0.6 m
- Wind
- 6 kn
- Gusts
- 9kn
- Air
- 30°C
Thu 5 · 89 out of 100
- Sea
- 0.6 m
- Wind
- 11 kn
- Gusts
- 18kn
- Air
- 30°C
Fri 6 · 89 out of 100
- Sea
- 0.6 m
- Wind
- 10 kn
- Gusts
- 14kn
- Air
- 30°C
Sat 7 · 91 out of 100
- Sea
- 0.5 m
- Wind
- 4 kn
- Gusts
- 6kn
- Air
- 29°C
Sun 8 · 90 out of 100
- Sea
- 0.4 m
- Wind
- 10 kn
- Gusts
- 13kn
- Air
- 30°C
Mon 9 · 89 out of 100
- Sea
- 0.4 m
- Wind
- 10 kn
- Gusts
- 14kn
- Air
- 31°C
Tap a day for sea, wind and water. Full forecast
Forecast: next 10 days
Full forecast- Mon 288, good
- Tue 389, good
- Wed 490, good
- Thu 589, good
- Fri 689, good
- Sat 791, good
- Sun 890, good
- Mon 989, good
- Tue 1088, good
- Wed 1171, good
The site in five facts
- Down to 18 mits deepest
- From a boathow you get in
- Open Waterand up
- Water 30 °Crash vest or 1 to 2 mm
- Faces Wswell from there reaches it
Full forecast
every day, every number
The score doesn't know currents, the visibility on the day or your certification.
Suits Open Water divers and up, as a dive guide states it. Scored for Advanced divers.
| Day | Score | Sea | Wind | Gusts | Air |
|---|---|---|---|---|---|
| Mon 2Nov | 88, good | 1.0 m | 1 kn | 8kn | 28°C |
| Tue 3Nov | 89, good | 0.6 m | 10 kn | 14kn | 30°C |
| Wed 4Nov | 90, good | 0.6 m | 6 kn | 9kn | 30°C |
| Thu 5Nov | 89, good | 0.6 m | 11 kn | 18kn | 30°C |
| Fri 6Nov | 89, good | 0.6 m | 10 kn | 14kn | 30°C |
| Sat 7Nov | 91, good | 0.5 m | 4 kn | 6kn | 29°C |
| Sun 8Nov | 90, good | 0.4 m | 10 kn | 13kn | 30°C |
| Mon 9Nov | 89, good | 0.4 m | 10 kn | 14kn | 31°C |
| Tue 10Nov | 88, good | 0.4 m | 8 kn | 11kn | 29°C |
| Wed 11Nov | 71, good | 0.4 m | 4 kn | 9kn | 30°C |
Sea is the waves near the site, in metres; wind and gusts in knots. "Boats in": gusts that keep dive boats in. More
Tide
- Mon 2 NovLow 07:07 −0.5 mHigh 14:48 +0.3 mLow 20:39 +0.0 m
- Tue 3 NovHigh 00:59 +0.2 mLow 08:12 −0.4 mHigh 15:32 +0.3 mLow 21:41 −0.1 m
- Wed 4 NovHigh 02:40 +0.2 mLow 09:17 −0.3 mHigh 16:11 +0.3 mLow 22:33 −0.1 m
Local clock times; heights about mean sea level. On open coasts the times are usually within a quarter of an hour; in bays, estuaries and on the Gulf of Mexico they can be an hour or more out. Slack water, the safest time to dive where there is current, is about half an hour either side of each high and low. Tide: EOT20 global ocean tide model, Hart-Davis et al. 2021, DGFI-TUM (doi:10.17882/79489), CC BY 4.0. Times and heights computed by us. A model, not a tide table: check a local table before you go.
Forecast updated . It refreshes every three hours. Forecast data: ECMWF, DWD, Météo-France and NOAA, served by Open-Meteo.com (CC BY 4.0). Changed by us. Generated using E.U. Copernicus Marine Service Information.
Best time to go
No month stands out
Good diving days in a typical week, each month, for Advanced divers, from 2016 on (ERA5 history scored the same way).
- Jan6of 7: a trip from Sat 2 Jan
- Feb7of 7: a trip from Sat 6 Feb
- Mar7of 7: a trip from Sat 6 Mar
- Apr7of 7: a trip from Sat 3 Apr
- May7of 7: a trip from Sat 1 May
- Jun7of 7: a trip from Sat 5 Jun
- Jul7of 7: a trip from Sat 3 Jul
- Aug7of 7: a trip from Sat 7 Aug
- Sep7of 7: a trip from Sat 4 Sept
- Oct7of 7: a trip from Sat 2 Oct
- Nov7of 7: a trip from Tue 3 Nov
- Dec7of 7: a trip from Sat 5 Dec
Tap a month to see this spot for a trip then.
Typical, not a forecast: the sea and the mean wind of each day, with no gusts or rain in the history.
Map
the site and its town
Hap's Reef on Google Maps · Directions
Each place wears its best day on these dates: green good, amber fair, pale red poor, as the key says.
The map needs JavaScript. Every place on it is listed on this page, and each place's page links to Google Maps.
One finger scrolls the page; two fingers move the map. Pins are our own positions. Map OpenFreeMap, © OpenMapTiles, data © OpenStreetMap contributors.
More diving near here
5 places
- Fish Eye Marine Park 5.7 km away
- Shark Pit 6.2 km away
- Blue Hole 6.4 km away
- Gab Gab Reef 7.3 km away
- SMS Cormoran 8.7 km away
About
the place in full, sources, credits
About Hap's Reef
A reef dive. It goes down to 18 m. You get in from a boat. It suits Open Water divers and up, as a dive guide states it. The coast faces W: swell from the W reaches it, and wind from the E blows out to sea. No dive centre within 10 km, the nearest 13 km away. The sea is about 28°C in February, its coldest month (3 mm wetsuit), and 30°C in June, its warmest (rash vest or 1 to 2 mm). The town to stay in is Agat. Within 5 km we also list 1 wind sports spot.
- What it is Reef.
- How deep Down to 18 m.
- Getting in From a boat.
- Who it suits Suits Open Water divers and up, as a dive guide states it.
- Dive centres No dive centre within 10 km, the nearest 13 km away.
Water about 30°C: rash vest or 1 to 2 mm. Typical sea temperature for the time of year, not a forecast.
Visibility over 30 m. Typical for the time of year, estimated from ten years of NASA satellite water clarity, not a forecast. Clearest in Jan, Feb, Mar, Nov and Dec (over 30 m).
The score is the conditions only: the journey, the price and the partners never change it (how we score, how we earn).
Rough cost (estimate): about US$1,220–US$2,390 each
about US$1,220–US$2,390 each · 6 nights, 2 sharing: flights, taxi, stay, food.
Our estimate from typical public prices, not a quote: check the real prices before you book (where they come from). Prices are about, in US Dollar (USD): our pound figures at the European Central Bank's rate of 2 November 2026.
How we worked it out
| What | How we worked it out | Each |
|---|---|---|
| Flights | return ORD to GUM, estimated from distance and season, changing at HNL, full-service airlines, with a hold bag | about US$751–US$1,560 |
| Taxi | airport and back, shared | about US$47–US$81 |
| Stay | 6 nights, a mid-range double, shared | about US$201–US$329 |
| Food | 7 days eating out | about US$221–US$416 |
| Total | about US$1,220–US$2,390 |
Guided dives are not priced yet: we have no sourced price, so it is not in it. Prices from public sources, checked in 2026.
Where to stay: Agat
Ad Links marked Ad may pay us if you book. You pay the same, and they never change a score. How we earn
about 5 min by car · 3 places to stay
About Agat its beds, food and every spot near it
Drives are estimates. Prices are about, in US Dollar (USD): our pound figures at the European Central Bank's rate of 2 November 2026.
Getting there: about 25h
About 25h door to door from Chicago
Fly ORD → GUM, changing at Daniel K. Inouye International Airport (HNL), then 40 min by road
Flights ORD → GUM on your dates · AviasalesAdeSIM for your phone · Search on AiraloAd
An estimate, one way; the journey never changes the score.
In the water
Dives and courses in Agat · GetYourGuideDive gear hire in Agat · GetYourGuide
Dive centres nearby
MDA (Piti Shop) 13 km
The nearest named dive centres and shops within 25 km, in a straight line; training agencies where the map states them. Listings, not a recommendation. Dive centres: © OpenStreetMap contributors (ODbL). Credits
What you might see
Animals divers and surveys have recorded within 2 km of this site in the last 15 years. A record says someone saw it here, not that you will.
Pomacentrus vaiuli
Seen in 24 records, mostly Mar to May.
Lavender Tang Acanthurus nigrofuscus
Seen in 13 records, mostly Mar.
Chrysiptera traceyi
Seen in 13 records, mostly Mar to May.
Clown Tang Naso lituratus
Seen in 11 records, mostly Mar.
Blackfin Cod Cephalopholis urodeta
Seen in 10 records, mostly Mar.
Chrysiptera brownriggii
Seen in 9 records.
Boomerang triggerfish Sufflamen bursa
Seen in 8 records.
Undulated Triggerfish Balistapus undulatus
Seen in 7 records.
Katherine's wrasse Cirrhilabrus katherinae
Seen in 7 records.
Lined Bristletooth Ctenochaetus striatus
Seen in 7 records.
Wrasse Labroides dimidiatus
Seen in 7 records.
Ringtail wrasse Oxycheilinus unifasciatus
Seen in 7 records.
Records: OBIS (Ocean Biodiversity Information System, IOC-UNESCO) and GBIF.org (1 November 2026, doi:10.15468/dl.jeesns), from the datasets named here, CC0 and CC BY records only. Names: WoRMS and GBIF; common names from the Catalogue of Life, the GBIF Backbone and Wikidata. Largest datasets here: NOAA Pacific Islands Fisheries Science Center, Ecosystem Sciences Division, National Coral Reef Monitoring Program: Stratified random surveys (StRS) of reef fish in the U.S. Pacific Islands; MIRC PIFSC CNMI Vessel Surveys May-Jul 2012. Credits
This week's visibility and the current no free forecast gives. Ask a dive centre before you book.