Of all the various different Turkish Mediterranean coastal resorts, Izmir stands out as being the one place where a hire car really isn’t absolutely necessary. There are few places on this coastline which have any kind of rail service at all, yet Izmir has both local and long-distance services, including a substantial urban rail network within the city.
If you are looking at venturing a little further afield, for example by taking a coastal driving tour up to the Dardanelles and the ancient site of Troy near Canakkale, or even continuing on to Gallipoli, then a hire car is still going to be useful.
Izmir is also one of the larger cities in Turkey (behind Istanbul, Ankara and Antalya), so it’s perfectly possible to stay within the city, rather than at one of the more purpose-built resorts along the coast.
You can also use local train or bus services to access ports for onward travel into Greece, and day trips are also available with various different tour bus operators to the historic site of Ephesus.
Do you need a car in Izmir? No!