The checklist nobody hands you — from controlling depth to the real monthly number.
Every marina listing has a depth figure. Almost none of them tell you what that number means. Is it mean lower low water? Mean low water? Chart datum? Measured at the slip, or at the approach? Was it surveyed last year or in 1987?
Call the marina and ask this exact question: "What is your controlling depth on approach at mean lower low water?" Controlling depth means the shallowest point on the approach, not the deep part of the slip. The dock master may not know off the top of their head — a good one will go look. If they give you a number immediately and confidently, ask when it was last dredged and whether there have been any shoaling complaints since.
Your draft is one number; your comfort margin is another. If you draw 5'6", a marina listed at 6' gives you six inches under your keel at the worst tidal state. That is not a comfort margin — that is a prayer. Most sailors with serious draft want at least 1.5 to 2 feet under the keel at the worst case. Do the math before you drive across three states to look at a slip.
The advertised spec is usually "30/50 amp service." What that doesn't tell you: whether the 50-amp pedestal is shared between two boats (common in older marinas built when 30A was the standard), whether the wiring is in good condition, and whether you'll be fighting another boat for amperage during the hottest weekend of summer.
If you run air conditioning, a 30-amp circuit is borderline at best. If you have two AC units, 50 amp dedicated is the floor. Liveaboards with any heat or cooling load should specifically ask whether pedestals are shared. "50 amp service" on a split pedestal means you effectively have 25 amps — not what the brochure implied.
Older marinas, particularly on the East Coast and Great Lakes, were built in the 1970s and wired accordingly. The slips may have been upgraded in name but the infrastructure feeding the docks hasn't. Ask how old the electrical system is. A marina that can't answer that question or gets defensive about it is telling you something.
In most US coastal states and all of the Great Lakes, you are legally prohibited from discharging untreated sewage overboard. The practical consequence: your holding tank fills, and at some point you need to empty it. The question is where.
Some marinas have an on-site pump-out station, either at the fuel dock or as a floating unit. Others do not, and expect you to go to the nearest pump-out facility — which may be two miles away and only accessible by dinghy if you're anchored. Before you commit to a slip, confirm: Is pump-out on-site? Is it self-serve or does it require calling ahead? Is it included in slip fees or is there a charge per use?
The pump-out situation at a marina is a surprisingly good indicator of how attentive the management is to practical sailor needs vs. the aesthetics of the parking lot.
Marina WiFi is almost universally terrible. Not "a little slow" — we mean streaming a single video is a coin flip, and forget about video calls. It's not the marina's fault: they're trying to share a single broadband connection across 200 boats, and the RF environment in a marina full of aluminum masts, stainless rigging, and metal hulls is genuinely hostile to 2.4GHz signals.
Plan your boat internet around cellular. A dedicated LTE/5G router with an external antenna — something like the Pepwave Surf SOHO or a WeBoost marine amplifier paired with a hotspot — will reliably outperform any marina WiFi. Budget for it. If cellular coverage at the marina is the question, check coverage maps before you arrive, not after.
The one exception: a few purpose-built modern marinas have invested in real marina-grade mesh networking with per-slip access points. You'll know because sailors talk about them. The ones that don't have it also don't usually admit it clearly in their marketing.
The advertised slip rate is rarely what you actually pay. Before you compare marina A at $12/foot to marina B at $15/foot, work out the full monthly number for each:
Add all of it up. The "cheaper" marina three miles down the road sometimes ends up more expensive once you factor in the electricity billing method and the monthly parking charge.
Transient rates are typically 2–4x the equivalent annual rate on a per-night basis. If you're spending more than about 90 days per year at a marina, the math usually favors an annual slip — even if you're not there the entire year.
The complication: annual slips at desirable marinas have waiting lists. At popular cruising destinations in the Pacific Northwest, Chesapeake, and New England, the waiting list for annual slips is 2–5 years at well-regarded facilities. Some marinas run a list so long they've stopped adding names. The protocol at most marinas is to put your name on the list even if you don't know exactly when you'll want the slip — you can always decline when your turn comes up.
A practical approach for cruisers without a home base: maintain a transient relationship with two or three marinas in your typical cruising range, spend enough time at each that the dock masters know your boat, and you'll frequently find that a slip opens up informally before your name comes up on the official list.
The most talked-about, most centrally located marina in a popular harbor is rarely the best value — and often not even the most pleasant place to be. The marina in the tourist district has the restaurant and the wifi sign and the pool, and it has transient boats rafting three-deep on holiday weekends, diesel exhaust from the fuel dock, and a party dock that goes until midnight on Saturdays.
The marina three miles up the estuary, or around the headland, or off the beaten cruising track, often has better holding, quieter nights, a dock master who actually knows all the boats, and rates that reflect the lack of foot traffic. The inconvenience of a longer dinghy ride or an extra taxi from the grocery store is often worth it.
Before committing to a marina based on location convenience, check whether there's a less-obvious option nearby. ActiveCaptain reviews from live-aboard cruisers — not marina guests who stayed one night for a boat show — are often the best source for this kind of comparison.
Five-star marina reviews are nearly useless. They're written by people who stayed one night, had a fine experience, and left. The useful reviews are the ones that mention specific operational details: whether the showers work, what happens when there's a power problem, how the staff handles a billing dispute, what the holding depth is on the north side of the T-dock.
Sources worth trusting: ActiveCaptain (integrated into Garmin chartplotters, reviews tend toward practical detail), the Cruisers Forum (liveaboards and long-distance cruisers who can be specific), and local sailing club forums and Facebook groups where regular visitors have deep familiarity with specific facilities. One-star reviews from marina users who got into a billing dispute are also often informative about how management handles problems — which tells you a lot.
Treat five-star reviews from accounts with one or two total reviews with particular skepticism. Marina management is not above soliciting reviews from charter guests on their way out the gate.
Call ahead — always. Even if the marina doesn't require advance reservations for transients, calling before you arrive accomplishes three things: it confirms the slip is available, it gives you approach and docking instructions, and it tells the dock master to expect you (meaning someone may be there to catch a line).
When you call, lead with your boat: "This is [vessel name], a [length] sloop with a [beam] beam and [draft] draft, looking for a transient slip tonight." Let them match the slip to the boat, not the other way around. Ask: "What are your approach instructions?" and "Will there be a dock hand?" If the answer to the second question is no, ask where they want you and which lines to lead first.
If you haven't been to this marina before, also ask: "Are there any depth concerns on your approach I should know about?" A good dock master will tell you. The ones who say "you'll be fine" without specifics are the ones whose approach you chart-plotter your way through very slowly, paying attention to the sounder.
For marina listings by region, visit the Marina Directory. For fuel dock procedures and provisioning advice, see the Fuel and Provisioning guide. For what to expect when your boat comes out of the water, see The Boatyard Haulout.