Getting There & Away
From about mid-April to mid-October Gareji Line runs a daily minibus between Tbilisi and Davit Gareja, departing at 11am from Pushkinis skver, just off Tavisuplebis moedani, and getting back there about 7pm. You get 2½ to three hours at Lavra and Udabno monasteries, plus a stop at Oasis Club on the way back. The ticket allows you to come back any day, so you can stay over at Oasis Club if you wish.
There are also day tours from Tbilisi with some hostels and agencies, or you can take a marshrutka from Navtlughi bus station to Sagarejo (3 GEL, one hour, every 20 minutes), and a taxi from there to Davit Gareja (return trip 60 GEL to 80 GEL).
From Sighnaghi, a taxi day trip to Davit Gareja costs around 100 GEL, or you could take a Tbilisi-bound marshrutka as far as Sagarejo and a taxi from there.
Marshrutky to Udabno village (6 GEL, 1½ hours) leave Navtlughi at 4pm on Monday, Wednesday, Friday and Sunday, making the return trip at 8.30am the same days.