Amelia Island State Park is located at the south end of the island. Follow A1A/First Coast Highway south, down past the Omni Amelia Island, and turn left just before the bridge. There is a limit to the number of people they allow so go early (hours are 8am-sundown). No after hours access is permitted. There is a $2 per person entry fee. Beach driving is allowed but you must have 4 wheel drive. You can also park and walk down to the river.
Bottom rigs such as a Fish Finder rig or Carolina rig along the river. You can also drive or hike around the southern point of Amelia Island, then north up the beach to a jetty that runs horizontal to the beach. You can wade out at low tide and fish the jetty with a bottom rig, or jig baited with live shrimp or artificial grub. Here’s more information
On The Line Bait and Tackle is located at the bridge.