Each of the multi-million pound rubber tyre gantry cranes can lift containers weighing up to 40 tonnes and stack them five-high.
The new cranes join an additional four RTGs which have been operational since the expansion of Teesport Container Terminal 2 in 2011.
A further investment order of £6m has been placed with Liebherr Container Cranes, to provide a ship to shore crane.
The firm’s latest purchases follow a £35m redevelopment which offers 550m of deep water quay-one of the deepest water facilities in the UK.
David Robinson, PD Ports’ chief executive officer, commented: “We’ve invested over £80m at Teesport over the past five years in developing, upgrading and enhancing capacity to meet the demands of our customers and position the Port as the northern gateway for containerised goods serving Northern UK markets.
“As Teesport continues to thrive in the container market, we must ensure the Port will have the right infrastructure and equipment to help provide shippers with more direct and efficient trade routes to northern markets.
“The addition of these cranes at Teesport provides a platform for further significant growth and ensures we continue to be a key driver and enabler of the Northern Powerhouse Strategy.
“Our continued investment in the Port will ensure it is fit for purpose to create new opportunities, attract inward investment and support sustainable growth across the North.”