State Road 686 (SR 686) is an east–west route in Pinellas County, running from Alt US 19 in Largo east to an intersection with State Road 687 (4th Street) and State Road 694 (Gandy Boulevard) in St. Petersburg, Florida.
State Road 686 begins at Alt US 19, running east as East Bay Drive. It runs through Largo, where it crosses an interchange with US 19 and east of the intersection, SR 686 is known as Roosevelt Boulevard, named for President Franklin Delano Roosevelt. It then travels in a southeastern direction through Clearwater, and intersects State Road 688 (Ulmerton Road), and heads east with a concurrency for just under a mile. At the end of the concurrency, SR 686 once again heads southeast, entering St. Petersburg. An interchange with Interstate 275 follows, and SR 686 ends at the intersection with SR 687 (4th Street) and SR 694 (Gandy Boulevard).
The entire route is in Pinellas County.