One of the biggest advantages of fly fishing is the ability to present your fly at different depths in the water.
While the fly itself influences how deep it fishes, the fly line usually has the greatest effect on presentation. Choosing the correct fly line is often more important than changing the fly pattern. If your fly isn't fishing where the fish are feeding, even the perfect imitation is unlikely to produce consistent results.
The type of fly line you need depends largely on the type of fishing you do. In the UK, different disciplines tend to favour different line densities.
## Floating Fly Lines
A floating fly line sits on the surface of the water.
It is by far the most versatile fly line available and is the standard choice for the vast majority of UK trout and grayling anglers.
Many newcomers assume floating lines are only used for dry fly fishing, but this isn't the case. A floating line is equally at home fishing:
* Dry flies.
* Emergers.
* Wet flies.
* Nymphs.
* Streamers.
* Dry dropper rigs.
* Indicator setups.
Depth is then adjusted using the leader, fly weight or sinking leaders such as polyleaders or VersiLeaders.
Because the line remains on the surface, it also provides excellent line control, making it easier to mend line and manage drag in flowing water.
For most UK river anglers, a quality weight forward floating line is all that is ever required.
## Intermediate Fly Lines
An intermediate fly line sinks slowly beneath the surface.
Rather than sitting on top of the water, it fishes just below it, helping maintain a more direct connection to the fly while reducing the effects of wind and surface drift.
Intermediate lines are less common for general river trout and grayling fishing but are widely used in other branches of fly fishing where keeping the fly just beneath the surface is important.
## Sinking Fly Lines
A sinking fly line is designed to take the fly deeper into the water column.
Unlike an intermediate line, sinking lines are available in a wide range of sink rates to suit different depths and water speeds.
Some sink slowly, while others are designed to fish very deep water.
We cover these in more detail in our guide to **Fly Line Sink Rates Explained**.
## Trout and Grayling Fishing
For the vast majority of UK river trout and grayling fishing, a floating line is all that is required.
Modern weighted nymphs, longer leaders and sinking polyleaders allow anglers to fish effectively throughout much of the water column while retaining the excellent line control that a floating line provides.
Although there are specialist situations where other line densities may be used, most river anglers will spend their entire fishing lives using little more than a floating line.
## Salmon Fishing
Salmon fly fishing is rather different.
Historically, many anglers carried several full sinking fly lines of different densities to match changing water conditions.
While these are still used, modern salmon fishing has increasingly moved towards interchangeable tip systems.
With systems such as Scandi and Skagit setups, anglers can often alter the fishing depth simply by changing the sink tip rather than replacing the entire fly line.
This makes it quicker to adapt to changing river levels, temperatures and water speeds while carrying fewer complete fly lines.
## Stillwater Trout Fishing
Stillwater trout anglers commonly carry several fly lines of different densities.
Fish may spend one part of the day feeding close to the surface before moving several feet deeper as conditions change.
Rather than continually changing flies, anglers often change the fly line to present the same pattern at the depth where the fish are feeding.
It's common for experienced stillwater anglers to carry floating, intermediate and several sinking lines to cover the full range of fishing situations.
## Pike Fly Fishing
Pike anglers also make regular use of different fly line densities.
A floating line may be ideal over shallow weed beds, while intermediate and sinking lines allow large flies to be presented deeper when fish are holding below the surface.
The correct choice depends on water depth, weed growth and where the pike are feeding.
## Saltwater Fly Fishing
Saltwater anglers also use a variety of fly line densities.
A floating line may be perfect when fish are feeding close to the surface, while intermediate and sinking lines allow flies to be presented deeper or held in stronger tidal currents.
The best choice depends on the target species, the depth of water and the conditions being fished.
## Which Should I Buy First?
If you're new to fly fishing, a quality weight forward floating line matched to your rod is the best place to start.
For most UK trout and grayling fishing, it will cover almost every situation you're likely to encounter.
As your fishing expands into stillwaters, salmon, pike or saltwater, you may find it beneficial to add intermediate or sinking lines to help cover a greater range of fishing depths.
## Related Articles
* Choosing a Fly Line.
* Fly Line Tapers Explained.
* Weight Forward vs Double Taper Fly Lines.
* Fly Line Sink Rates Explained.
* Integrated Fly Lines vs Shooting Heads.
## Peaks Fly Fishing Tips
* A floating line is the only fly line many UK trout and grayling anglers will ever need.
* Don't assume you need a sinking line to fish subsurface - weighted flies and sinking leaders can cover a surprising range of depths.
* Stillwater, pike and saltwater anglers often carry several fly lines of different densities to match changing conditions.
* Modern salmon anglers commonly adjust depth by changing interchangeable sink tips rather than replacing the entire fly line.
* Before changing your fly, ask whether you're fishing at the right depth.
