Lop Buri can be reached by bus, train, mini van or car from Bangkok , Ayutthya and other nearby cities such as Singburi and Saraburi.
There are buses running from Bangkok to Lop Buri. However, they are not direct buses. If you board at Bangkok, you have to get down at Saraburi and then catch Nakhon Sawan bus from there to reach Lopburi. The time from Nakhon Sawan might take upto four hours and around six buses ply daily. Direct buses are available from Singburi, Ang Thong, Phetchabun and Nakhon Sawan. Similarly, air conditioned mini vans also operate daily from Mo Chit in Bangkok and it usually takes around 4-5 hours and the cost is generally 100 -150 bht and the last mini van leaves Bangkok by 6 pm. Mini vans leave from city centre in Ayutthya and the cost ranges from 80-100 bht. Likewise, mini vans also leave from Bus Stations in Ang Thong and Saraburi and the ticket costs 30 -80 Bht.
Lopburi doesn't really have any tuk tuks. The city can be explored on foot as the places lie within a walkable distance from each other.Otherwise, Songthaews which are pickup trucks with two bench seats is the common means of transport. They can be easily spotted along the Wichayen and Phra Narai Maharat roads, connecting the old and the new town. They will be red/brown, white or green in colour and just wave your hand at the Songthaew to pick you up. They usually don't operate after 6 pm, so it is better to wind up your outdoor activities before six in the evening