Deep sea fishing is recreational or commercial fishing done in open ocean waters, typically over depths of at least 100 feet and often much farther offshore where the continental shelf drops away. It targets large, powerful species like marlin, tuna, swordfish, and mahi-mahi that rarely come close to shore. What separates it from inshore or nearshore fishing is the depth of water, the distance from land, the size of the boat required, and the heavy-duty gear involved.
How Deep and How Far Out
There’s no single universal cutoff, but deep sea fishing generally starts where inshore fishing ends. Most charter operations consider anything beyond about 30 meters (roughly 100 feet) of water depth to be deep sea territory. The Food and Agriculture Organization of the United Nations uses 200 meters as a benchmark for deep-sea fisheries, which applies more to commercial operations over continental shelves, seamounts, and underwater ridges. For recreational anglers, the practical definition is simpler: you’re heading miles offshore, often 20 to 50 miles or more, into water where you can no longer see the bottom and the ocean floor may be hundreds or thousands of feet below.
That distance from shore matters because it determines what fish are available. Pelagic species, the big ocean roamers, spend their lives in open water following currents, temperature breaks, and schools of baitfish. To reach them, you need a capable boat, a knowledgeable captain, and enough time to make the run out and back.
Species You Can Target
The International Game Fish Association recognizes dozens of offshore game fish, and what you’ll encounter depends heavily on your location and the season. The marquee species that draw most anglers offshore fall into a few groups.
- Billfish: Blue marlin, white marlin, striped marlin, black marlin, sailfish, and swordfish. These are the iconic trophy fish of deep sea fishing, known for explosive strikes and acrobatic fights. Most billfish are now catch-and-release only in many regions.
- Tuna: Yellowfin, bluefin, bigeye, blackfin, and albacore. Tuna are among the fastest and strongest fish in the ocean, and bluefin in particular can exceed 1,000 pounds.
- Other pelagic species: Mahi-mahi (dolphinfish), wahoo, king mackerel, and cobia. These are fast, aggressive fish that often travel near the surface and respond well to trolled lures.
- Sharks: Mako, thresher, hammerhead, blacktip, and tiger sharks are all encountered offshore. Regulations vary widely by species and region, with some sharks fully protected.
- Bottom dwellers: Grouper, snapper, amberjack, and tilefish live near reefs, wrecks, and ledges in deep water. These are targeted with a completely different technique than pelagic fish.
Trolling, Bottom Fishing, and Jigging
Deep sea fishing isn’t a single technique. The method you use depends entirely on what you’re after.
Trolling is the most common approach for pelagic species. The boat moves at a steady speed, usually 5 to 10 knots, while dragging multiple lines behind it at varying depths. Each line trails a skirted lure or rigged bait designed to mimic a fleeing fish. Rod holders along the gunwales and outriggers (long poles extending from the sides of the boat) spread the lines apart to cover more water and prevent tangling. When a fish strikes, the line releases from the outrigger clip and the angler grabs the rod to fight the fish.
Bottom fishing takes the opposite approach. The boat anchors or drifts slowly over a reef, wreck, or rocky ledge, and anglers drop weighted rigs straight down to the seafloor. Natural bait like squid or small fish sits near the structure where grouper, snapper, and amberjack feed. This technique is less about covering ground and more about knowing where the fish live. Circle hooks are standard for bottom fishing because they hook the fish in the corner of the mouth, making release easier and reducing gut-hooking.
Vertical jigging is a more active technique where anglers repeatedly drop and retrieve heavy metal lures through the water column. It’s physically demanding but effective for amberjack, tuna, and other species that feed at mid-depths.
Specialized Gear and Electronics
The tackle used offshore is significantly heavier than freshwater or inshore gear. Reels hold hundreds of yards of line rated to withstand 30, 50, 80, or even 130 pounds of drag pressure. Rods are shorter and stiffer than their inshore counterparts, built to leverage large fish upward from deep water. For trolling, boats carry high-capacity reels designed for speed and sustained drag.
Downriggers are another important tool, especially when fish are feeding below the surface. A downrigger uses a weighted ball on a cable to pull your bait or lure down to a precise depth. This is particularly useful when fish are holding near a thermocline, which is a layer where water temperature changes sharply. Modern fish finders display thermoclines as a visible band on screen, letting captains position baits exactly where fish are congregating. Wahoo, for example, often prefer a subsurface presentation, and a downrigger lets you troll a lure at 30, 50, or even 100 feet below the surface while the boat moves forward.
Fish-finding sonar and GPS are essential for offshore work. Captains use them to locate underwater structure, mark productive spots, identify water temperature breaks, and even spot schools of bait or fish in the water column.
What Kind of Boat You Need
Deep sea fishing requires a vessel built for open ocean conditions. For recreational anglers on charter trips, center console boats in the 28- to 42-foot range are common. These are fast enough to reach offshore grounds quickly and stable enough to handle moderate seas. Sportfishing yachts, typically 40 to 80 feet, offer more comfort and range for longer trips, with features like fighting chairs, tuna towers for spotting fish, live bait wells, and enclosed cabins.
The key features that separate an offshore boat from a bay boat are a deep-V hull for cutting through waves, high freeboard to keep water out, reliable twin engines for safety, and enough fuel capacity for a round trip that might cover 100 miles or more. Commercial offshore fishing vessels are much larger, running 30 to 100 meters in length with deep draft hulls and wide beams for multi-day trips.
What a Charter Trip Looks Like
Most people experience deep sea fishing through a charter, where you book a trip on a captain’s boat with gear, bait, and expertise included. Half-day trips typically run 4 to 6 hours and cost $75 to $150 per person. Full-day trips last 8 to 12 hours and range from $150 to $300 per person. Private charters, where your group has the boat to yourselves, cost more but offer a more tailored experience.
Charters generally provide all rods, reels, tackle, and bait. Some include food and drinks; others expect you to bring your own, so it’s worth asking ahead. You’ll also need a fishing license in most jurisdictions, though many charter captains hold a blanket license that covers everyone on board. Expect to tip the mate 15 to 20 percent if the service is good.
A typical offshore day starts early, often at dawn, with a 45-minute to two-hour run to the fishing grounds depending on location. Once there, the captain reads water temperature, current, and electronics to decide where to set up. You might troll for a few hours, then anchor over a wreck for bottom fishing, or focus entirely on one technique depending on conditions and your target species.
Catch and Release Practices
Many offshore species, particularly billfish, are managed through catch-and-release regulations. Even where keeping fish is legal, releasing them properly is increasingly the norm among sport fishers. The practices that give a released fish the best chance of survival are straightforward but important.
Use tackle heavy enough to land the fish quickly rather than fighting it to exhaustion. Circle hooks and barbless hooks make removal faster and cause less damage. If a hook is swallowed, cutting the line close to the hook is better than trying to dig it out. Non-stainless hooks corrode and fall out on their own over time. Handle the fish as little as possible, only with wet hands, and keep it in the water during unhooking whenever you can. If you lift a fish for a photo, support its full body weight and limit air exposure to under 60 seconds.
Fish brought up from depths greater than about 30 feet can suffer from barotrauma, where expanding gases trapped in the body prevent the fish from swimming back down. Descender devices, which clip to the fish and carry it back to depth before releasing, are the best solution. Some fisheries now require anglers to carry descending tools on board.