In Phuket bikes are available for rent to go around
if more people then tuk tuk is the best option. taxis also available but the people not very friendly. Always display your hotel visiting card when you need to be dropped back as people find it difficult to follow our accent. it's a small city, Phi phi island tour is the main attraction.
Important part it to keep your passports safe..better in hotel locker and carry copies with you..don’t keep money all at one place,specially in wallet..have all contacts pen down just in case you need help especially of the local security or police..don’t travel on lone places at night..be safe!rest is HAPPY TRAVELLING
In Phuket you will find bike taxis and songthews to travel within the city. Tuktuks are avilable in krabi. It is safe but beware of pickpockets. Thailand is currently providing visa on arrival for free til Oct 31.