I have a Hong Kong Airlines flight booked landing at Okinawa Naha airport at 15:00 on a Sunday. Our plans have changed slightly and we now want to fly immediately on to Ishigaki that same day. It'll be a self-transfer, so we'll need to wait at baggage reclaim, pass through immigration and customs, drop of our bags again and pass through security. We're British passport holders who have never been to Japan before; I've no reason suppose we will have any difficulty at immigration.
There is a very convenient onwards flight with Japan Transocean Air at 18:15 which gives 3h15 to transfer. Is this long enough? Hong Kong Airlines seem pretty reliable. Missing the connection would not be a total disaster: I'm sure we can find a hotel at short notice and book on to a morning flight, but it would set the holiday off to a bad start.