Carris announced that the new surface metro, route 16E, will open in 2029, a year later than initially planned.

The line will connect Praça do Comércio to Parque Tejo, with commercial service launching in phases. The first phase will link Terreiro do Paço to Santa Apolónia in 2029. Trains will reach Parque das Nações in 2031.

The announcement was formalised by Rui Lopo, president of the municipal transport company, who detailed that the technical services are finalising the proposed route for the section between Santa Apolónia and Parque Tejo, which will have to undergo an environmental impact assessment.

He also revealed two alternative routes to the original plan outlined by the previous city council. The major innovation of the 16E tram will lie in its operational configuration, as it will circulate in a dedicated lane segregated from the rest of the car traffic, an unprecedented model in the current Carris tram network, and will also benefit from a priority system at traffic-light intersections.

The new line will span 12 kilometres with 18 stops. The trip from Praça do Comércio to the southern flank of Parque das Nações takes 15 minutes, or 35 minutes to the Parque Tejo terminal. The main route follows Alameda dos Oceanos through the Expo area, but Carris has developed alternative routes should the Environmental Impact Statement find obstacles.

At Parque das Nações, the tram connects directly with the future Loures BRT (rapid electric buses in a dedicated lane) and major transit routes, such as Santa Apolónia and Gare do Oriente rail and metro lines, Transtejo/Soflusa ferries at Terreiro do Paço, and the planned river dock for Parque das Nações.

The complete route of line 16E will be structured along a continuous corridor that starts at Terreiro do Paço and continues towards the Cruise Terminal and Santa Apolónia station.

From there, the tram runs along the riverside area, passing through Mouzinho de Albuquerque, Xabregas, the Unicorn Factory and Marvila, before crossing Poço do Bispo, Braço de Prata and Matinha. Upon entering the modern part of the city, the line serves Parque das Nações Sul, the Oceanário, Oriente Station, and the Vasco da Gama Tower, then continues along Alameda dos Oceanos Norte and Rotunda da Colômbia until reaching Parque Tejo, where it ends its route at Parque das Nações Norte.