Most services on the East Suffolk Line are provided
by modern Class 170 trains, known as Turbostars. These diesel multiple units (DMUs) feature both first and standard class, 2+1 seating in first class, 2+2 in standard class, air conditioning, and modern toilets. They have a top design speed of 100 mph. Many of these trains continue on to London Liverpool Street.

Freight locomotives servicing the Sizewell power station can be seen on the southern portion of the East Suffolk Line from Saxmundham to Ipswich; these trains travel on the old Aldeburgh branchline which now ends at Leiston. Container trains from the port of Felixstowe use the line from Westerfield to Ipswich.

From 1994 to late 2004 almost all services on the line were handled by class 150 two-car and class 153 single-car DMUs known as "Sprinters". A Class 170 was used for the one daily direct-to-London service  from 1999 to late 2004. Six direct services were added in December 2004, all using 170s. In 2005 the 150s were replaced by newer class 156 Super Sprinter two-car DMUs for services terminating at Ipswich.

Locomotive hauled passenger trains were prohibited from using the line after a radio electronic token block system was installed in the early 1980s. Class 101 units handled most passenger services until 1993.