Florida Keys snorkeling and diving week: Key Largo to Key West

Why this trip moves slowly down the Overseas Highway

Most visitors treat the Florida Keys as a single long day from Miami: drive to Key West, take a photo at the buoy, drive back. That works if you want to say you have been there. It does not work if you actually want to get in the water. The drive alone is about 160 miles (257 km) one way, and 3.5 to 4 hours of driving each way without stops — more once weekend traffic on the Overseas Highway is added in. Doing that twice in one day leaves almost no time to dive or snorkel anywhere.

This itinerary treats the same stretch of road as a chain of bases instead: Key Largo first because it is closest and gets you in the water on day one, Islamorada for a day that leans more toward fishing and land-based stops, Marathon as the hinge point roughly halfway down the chain, and Key West at the end for a longer stay. Reef and dive site detail for each stop lives on the destination pages linked above; this page is about the pacing and the order.

A rental car is not optional here. You will drive on the right, on a two-lane highway for long stretches, with 42 bridges between Key Largo and Key West. Fill the tank before you need to and do not expect quick detours — the Keys are effectively one road. If this is your first time renting in South Florida, the Miami car rental, tolls and parking guide covers the toll transponders and one-way fees that catch first-time drivers out before they even leave the airport.

Before you go: timing, gear, and what to skip

Late spring through early summer tends to bring the calmest water and the best underwater visibility in the Keys, though the dive shops and charter boats run year-round. Whatever week you pick, check it against hurricane season (June 1 to November 30, peaking August through October) and against the best time to visit Miami guide, since the weather pattern that shapes Miami also shapes the water conditions down the chain. Pack reef-safe sunscreen specifically — several dive operators in the Keys will not let you in the water with the oxybenzone-based kind — along with a rash guard for reef time and closed shoes for the handful of land stops. The Miami packing guide covers the rest of the warm-weather basics that apply just as much in the Keys.

Skip the temptation to add a full day in Miami at either end of this trip unless you have already covered the city. This itinerary is built around water time, not sightseeing, and every extra night in Miami is a night not spent snorkeling somewhere between Key Largo and Key West.

Day 1: Miami to Key Largo

Leave Miami in the morning rather than after lunch; the drive to Key Largo is a relatively short 55 to 60 miles (about 90 to 95 km), an hour or so without traffic, but it is worth arriving with enough daylight to get in the water the same afternoon.

Head straight to John Pennekamp Coral Reef State Park, the first protected reef in the continental United States and still one of the most accessible for snorkeling without a long boat ride. A glass-bottom boat tour or a snorkeling trip out of the park covers the shallow reef sections without requiring certification.

End the day on the water rather than in a restaurant queue: a Key Largo sunset cruise is a low-effort way to see the mangrove channels and open water light without planning a full excursion. For more of what Key Largo offers beyond the park, see Key Largo snorkeling and diving and Key Largo boat tours and cruises.

Day 2: Key Largo diving and reef time

Stay a second night in Key Largo and use the full day on or under the water. Certified divers have the most options here — Molasses Reef and the wreck of the Duane are among the better-known sites, and dive shops run two-tank trips most mornings. Snorkelers have plenty to see at the shallower patch reefs without the extra certification and gear.

If you want a slower option that still gets you on the water without a dive shop schedule, a two-hour sandbar boat trip out of Key Largo fills an afternoon well, especially if the morning went to a dive charter. Book any dive trip a day or two ahead in high season; boats do fill.

Day 3: Key Largo to Islamorada

The drive to Islamorada is short, under 20 miles (about 30 km), so there is no need to rush the morning. Islamorada markets itself as the sport fishing capital of the Keys, and it is worth leaning into that rather than trying to replicate Key Largo’s reef diving here.

A full-day fishing charter out of Islamorada is the obvious choice for anyone who wants to fish rather than dive on this stop. For a slower, less gear-heavy afternoon, Theater of the Sea offers a look at marine life without a boat at all — useful if the morning charter runs long or the weather turns. More on the area’s water-based options is on the Miami and Keys sport fishing guide.

Day 4: Islamorada to Marathon

Another short hop, roughly 25 miles (40 km), to Marathon. This is the roughly halfway point of the chain, and the town has two landmarks worth building the day around: the Seven Mile Bridge, the longest of the 42 bridges on the route and a genuine stretch of open water on both sides, and the Turtle Hospital, a working rehabilitation center for injured sea turtles that runs guided tours.

Spend the morning on land at these two stops, then move to the water in the afternoon. A floating tiki boat cruise around Marathon is a lighter option if the previous two days involved heavier dive or fishing schedules and a slower afternoon is welcome.

Day 5: Marathon reef and sandbar day

Use a full day in Marathon rather than pushing straight to Key West. Sombrero Reef, just offshore, is a snorkeling and diving spot with a lighthouse marker and less boat traffic than the more heavily visited sites further north.

A

sandbar boat tour with lunch out of Marathon

covers a full afternoon on the water with a built-in meal, useful on a day you would rather not plan around restaurant timing. Anyone traveling with a non-diver in the group will find Marathon’s mix of reef access and calmer sandbar spots easier to split between different comfort levels than Key Largo’s more dive-focused sites.

Day 6: Marathon to Key West

The final leg is the longest single stretch of the week: about 45 to 50 miles (roughly 75 to 80 km) from Marathon to Key West, but still under an hour and a half without heavy traffic, since you are already deep into the island chain by this point.

Once in Key West, resist the urge to pack the whole visit into one day. Walk Duval Street and see the Southernmost Point buoy — a marker rather than the literal southernmost spot in the continental United States, as the mile marker zero explainer lays out — and save the water time for the following day. This is also the point where Key West’s history and Ernest Hemingway connections are easiest to work in, since they do not depend on calm seas or daylight.

Day 7: Key West diving, snorkeling, and the Dry Tortugas option

Key West sits closer to a healthy stretch of reef than Marathon or Islamorada, and it is also the departure point for the Dry Tortugas, so this last full day has two directions to choose from.

For reef time without leaving the main island chain, book a

tiki party boat out of Key West

for an easy afternoon, or arrange a dedicated snorkeling or diving trip through Key West snorkeling and diving if reef time is the priority over a leisure cruise.

If you have an extra day to spare — this itinerary as written does not budget one — the Dry Tortugas National Park is worth naming honestly: it sits about 70 miles west of Key West, and there is no road there and no shortcut from Key Largo, Islamorada or Marathon. The only ways in are the official park ferry, a seaplane, or a private or authorized charter boat, and seats are limited enough that booking weeks ahead is normal, not excessive caution. Treat it as a possible eighth day, not something to squeeze into this one.

Non-divers or anyone who wants a day out of the water without losing the Key West evening are better served by the history and ghost tour options already mentioned for Day 6, or by a slower morning with a Key West food and drink tour before an afternoon back on the water. Paddle-based options through Key West kayaking and paddleboarding are also worth a look for a lower-key alternative to a dive charter, and dolphin sightings are common enough on Key West boat trips that a dedicated dolphin and wildlife tour is worth booking before defaulting to a generic charter.

Before flying or driving back to Miami, a quick read of Key Largo versus Key West as a single day trip is a useful sanity check on why this slower route works better for diving specifically, even if a future trip only has time for one end of the chain.

If a week is too much, or not enough

Not every trip has seven days to give to the Keys alone. If Key West is the only stop that matters and the reef time in Key Largo and Marathon can wait for another visit, the Miami to Key West road trip covers the same highway in less time. Going the other direction, if a week in the Keys still leaves days spare, seven days in Miami and the Florida Keys splits the time between the city and the chain instead of spending it all on the water, and ten days in South Florida stretches the same route further north to add Fort Lauderdale or Palm Beach on either end.

Planning notes for this route

Stop	Distance from Miami	Suggested nights	Main draw
Key Largo	~55–60 miles (90–95 km)	2	John Pennekamp Coral Reef State Park, wreck and reef diving
Islamorada	~75–80 miles (120–130 km)	1	Sport fishing, Theater of the Sea
Marathon	~100–105 miles (160–170 km)	2	Seven Mile Bridge, Turtle Hospital, Sombrero Reef
Key West	~160 miles (257 km)	2–3	Duval Street, reef access, Dry Tortugas departure

A few things to keep in mind before booking:

• Hurricane season runs June 1 to November 30 (NOAA), with the highest activity from August to October. Travel insurance and flexible cancellation policies are worth the small extra cost in those months, and no honest guide will tell you whether a storm is likely on your specific dates. See the Miami and Florida hurricane season guide for how to plan around it.
• Entry rules: travelers from Visa Waiver Program countries need an ESTA, which is a travel authorization, not a visa, and should only be applied for at esta.cbp.dhs.gov. Details are on the ESTA and entry rules guide.
• Prices for charters and boat tours move with season and fuel costs. Treat any figure here as a rough range and check the current price on the booking page before committing a date.
• Book dive and fishing charters a few days ahead in high season (roughly November through April), when boats fill faster and last-minute slots are scarce.
• Tipping is expected on charters, at dive shops, and at restaurants along the route, generally in the same 18 to 20 percent range as the rest of Florida. The Miami tipping, taxes and resort fees guide covers what that looks like in practice, and it applies just as much in the Keys as it does back in Miami.
• Reef conditions vary by site and season. For a plainer explanation of why some patch reefs look better than others on a given day, and how the Florida Reef Tract differs from a single dive site, see the Florida Keys coral reef explainer.