All of these temples can be visited in one day from Malang by public transport and with the addition of ojeks if you want to speed things up.
Candi Singosari is a pretty temple located about 12 kilometres north of Malang built in the early 14th century to commemorate the death of Kertanegara, the last king of the Singosari dynasty who according to legend died in 1292. The temple itself climbs to a height of 15 metres and cuts an impressive figure in an otherwise uninteresting village street. Restoration commenced in 1934 and concluded in 1936.
Candi Singosari is easily accessible by public transport from the Arjosari bus terminal, five kilometres north of town. Light green angkot with the letters LA ply the route from Arjosari to Singosari regularly for 2,000 rupiah and can drop you off outside the Indomaret which sits on the corner of the main road and the road to Candi Singosari. The temple is 300 metres along this road and can't be missed. Walk a further 200 metres to reach a pair of plump four-metre tall dwarapala statues adorned in skull earrings and serpents, arguably as impressive as the main temple. Both the temple and dwarapala require a 2,000 rupiah donation for entry.
For onward travel, angkots leave from the nearby market on the main road 500 metres south of the Candi Singosari turn off.
Dating from the 14th century, this part restored/part rebuilt Buddhist stupa sits in the middle of a forest in the village of Toyomarto six kilometres up from Singosari in the foothills of Mount Arjuna. It's a mildly interesting site, but probably isn't worth the hassle of getting to if you are using angkots only – use of an ojek or private vehicle is recommended.
Royal blue angkots depart for Sumberawan from the Singosari market (2,500 rupiah) only when there are enough passengers. Early in the day, this usually means they depart every 45 minutes. Angkots will drop you off at the path leading to the temple, which runs alongside an irrigation ditch for about 500 metres. Ojeks will take passengers here and back from the market in Singosari for 20,000 rupiah.
Discovered in 1928 by the Dutch, Candi Jago is a temple of both Hindu and Buddhist significance located 24 kilometres southeast of the Arjosari bus terminal in the town of Tumpang. The temple is the largest and most impressive of those surrounding Malang and features an abundance of intricate reliefs depicting stories such as the Ramayana and Mahabharata. It's possible to climb this temple and get a decent view of the surrounding town.
From the Arjosari bus terminal, catch a white Tumpang-bound angkot for 5,000 rupiah. It will drop you off on the corner of Jalan Wisnuwardana across from the mosque. It is not necessary to catch one of the horse and carts for the 300 metre journey up Jalan Wisnuwardana to the temple.
Candi Kidal is a very impressive Hindu/Buddhist temple located a further seven kilometres from Candi Jago. It was built in 1248 as a burial shrine to King Anusapati and to this day remains a stunning example of East Javanese design from that period, with intricate decorations adorning many of the surfaces. It's a temple certainly worth the considerable effort of visiting.
Angkots depart from the Tumpang market for 2,000 rupiah, 200 metres east of the turn off to Candi Jago, but only when full. This can pose problems later in the day when fewer passengers wish to travel along this route. An ojek can be hired for 20,000 rupiah for the return journey and is probably the most practical option for independent travellers.