Plan the city and the wider island separately.
Ishigaki City is a useful beginning: restaurants, shops and everyday facilities give you a chance to settle in before travelling farther. Walking can work well for a day centred on the town. For journeys beyond it, look at the whole route, including the return, before deciding that a bus or taxi will meet your needs.
The airport provides links to bus timetables and information about taxis. Use those current details to connect your arrival with your accommodation. For a countryside day, compare the actual stops and departures with the places you want to visit; a route on a map does not tell you how much time you will have there.
A car makes more of Ishigaki possible.
For exploring beyond the centre, we strongly recommend a rental car, especially when travelling with children. The north, the mountains and the stretches of coast between villages deserve time. A car gives you more freedom to choose your stops and carry the things you need for the day.
Think about meals, parking and the return to your accommodation as well as the outward drive. If you want only one countryside day, compare a short rental with keeping a car throughout your stay. Confirm collection arrangements, luggage space, any child seats and the rental terms with the company before committing.
Choose two wheels for the right kind of day.
For Taketomi, our suggestion is straightforward: rent a bicycle and explore the village and the rest of the small island. Stop to look at the houses and spend time by the sea before returning to the port.
On Ishigaki, a bicycle or scooter is a more deliberate choice. Consider the distance, your experience, the weather and the things you need to carry. Ask the rental shop about the particular vehicle and your proposed route; do not assume that an electric bicycle and an electric scooter have the same operating or licence requirements.
The crossing is only part of the journey.
Before taking a ferry, decide how you will travel after arriving and how you will get back to the port. On Iriomote, we recommend arranging an activity if you want to experience the forest and rivers beyond the main road. A ferry ticket on its own does not organise that part of the day.
Sea connections serve the people who live here as well as visitors. Weather can change what is possible, so check the operator's current information and leave room to adjust. If your return connects with a flight or another booking, think through what a delayed crossing would mean before making the plan.
Check the official requirements before renting.
Use Japan's National Police Agency guidance to check the documents and rules that apply to your licence and the vehicle you want to use. Then confirm the rental company's requirements. Do this before collection day, while you can still make arrangements.
A flexible route is useful in ordinary changing weather, but a vehicle is not a reason to continue with an outing when conditions deteriorate. Follow current local instructions and the advice of the relevant transport or activity provider. Sometimes the workable plan is to stay put.