Yep it's a long walk.... lemme post up some pics and directions.
there isn't an easier way.
It's best to dive this about an hour before/after "high slack tide" for best vis and lowest current. consult tide charts in planning your dive. You'll want to look for "Destin East Pass".
EDIT: here are the pics/directions. Some of these pics I took, some are off the web. some by other folks like Sea Yoda, PHD, and maybe a few others.
Most folks dive the "Finger jetty" on the east side of the pass/channel as seen below
You'll want to turn on Gulf Shore drive in the Holiday Isle area and follow it towards the end of the road.
look for the beach access sign seen below on your left
There is also a showerhead on the left (circled red). (pic taken before the new beach access sign. You'll want to park on the right as shown by the arrow. There is a long section to park on the right side of the road. parking gets crowed on warm weekends. so get there early
best to gear up and your car and carry only what you need for the dive.
The view going down the beach access. head straight for the water and then turn left at the water and walk on the "hard packed" sand around the shoreline. much easier to walk on than the soft sand
When you get to the end of the shoreline, you'll see the finger jetty running out to your right. This is the part of the jetty that most people dive on
The oposite side of the same jetty. some people dive this side also, but mostly by just circling around the tip of the jetty and coming back up it. (depending on currents, etc)
A couple pics by SeaYoda. His "Sand Yacht"