A reach cast allows you to reposition your line, upstream or downstream of the fly, before the line lands on the water. This comes in handy whenever you’re casting across the current, and it’s actually easier to accomplish than the standard mend. Since mending occurs after the line has touched down, you have to fight the surface tension of the water, and some folks struggle with mending only the part of the line affected by the current. (Here’s a good primer on mending.) In the video above, I demonstrate how to make a reach cast, and once you’ve got the hang of the reach cast, it will become second nature to you.
There are a couple keys to making a proper reach cast. First, you have to wait until the forward cast is complete before you move the rod upstream or downstream. Otherwise, your accuracy will suffer. Second, allow some of the slack in your line hand to slide upward through the guides as you move the rod, which will keep you from accidentally jerking the fly backward and out of the fish’s strike zone. If you’ve laid the line on the water properly, you’ll get an excellent, long dead-drift, which means that you have a better chance of catching fish. Good luck!