JR Kamata (railway station) and Shinjuku Sanchome (subway station) are somewhat different types of station, but both of them have coin lockers
Sanchome (near exit E5)
http://www.tokyometro.jp/station/shi...chome/yardmap/
Kamata (Two locations near the southern exit)
http://www.jreast.co.jp/estation/stations/478.html