During the day every line runs on average every 5–10 minutes, but almost every station serves at least two routes.

City fathers started discussing the idea of installing horsecar system in Zagreb.

Trams should have been put in service on 15 August 1891, on the opening day of the Jubilee Economic-Forestry Exhibition.

That day was officially taken as the beginning of organised public transit system in Zagreb.

Line 16 used to connect Črnomerec and Zapruđe, but it was discontinued in 1991, due to a shortage of drivers when the Croatian war of independence started.

Night-time lines are often substituted by buses due to track maintenance and repairs.

ZET used to have a total of 30 TMK-201 units with 32 trailers, of which nine remain in use, as some were scrapped and their bases were reused in the production of TMK 2100s.

They were brought as a temporary solution, as the lack of funds prevented the buying of new vehicles.

In 2003 ZET ordered 70 new 100% low-floor trams from Crotram, a consortium led by Končar.

It has air-conditioning, cameras outside (instead of rear view mirrors) and inside; its maximum speed is limited to 50 km/h.

[6] The last car from the second order entered service on June 30, 2010, meaning that currently there are 140 TMK 2200 trams operating in Zagreb.

The city hopes to operate uniformed tram type by the end of decade, with TMK 2100 relegated to night service only.

[11] In 2024., ZET signed contracts with Končar to procure a total of 40 new trams worth €80 million[12].