2008 - VIP Terminal was added and extra amenities, restaurants and bars. Terminal expanded to 15,500 m2 (167,000 sq ft) 
2010 - 3rd Floor Viewing platform and a bar were added, passenger terminal received major facelift.
2012- 2013 - Additional 5,872 m2 (63,210 sq ft), of space being added, with completion dates sometimes in mid to late 2013. Terminal expanded to 22,500 m2 (242,000 sq ft) with increased capacity up to 3.5 million passengers. Airport had also most successful year ever with 2.34 million passengers passing through its gates.
2013-2016 - Construction of new 70,000 m2 (750,000 sq ft) passenger terminal should commence in August or at the latest in September, 70,000 m2 (750,000 sq ft) terminal with capacity of 5.5 million passengers in the first phase should be completed by mid to late 2016, 250,000 m2 (2,700,000 sq ft) Airport apron/Airport Ramp will also be added as part of the whole expansion project.
The passenger terminal underwent major design upgrade, new VIP terminal was added to the west of the current terminal in 2008, and new unified facade (at the front of the terminal) was also added in 2009. The passenger terminal has a maximum capacity of around 2.5 million passengers per year with current traffic being around the 2.2 million mark. The main terminal building itself is rather small measuring only 200 × 58 m (660 × 190 ft) or around 20,000 m2 (220,000 sq ft). The apron or airport ramp measures 950 × 187 m (3,120 × 614 ft) and can accommodate around 15 medium and two wide body aircraft. The terminal is planned to accommodate low-cost flights after the construction of the second terminal.
A new terminal is planned for the future. The initial plan, made by NACO in 1997, was for 47,000 m² of space, capacity for 11 jetways, and the capability of handling 3 million passengers annually, but the airport authority decided to scrap this plan in favor of a larger terminal. Another master plan was developed by Scott Associates in 2006 and the new terminal was expected to have 12 jetways and a capacity of 3.3 million passengers annually. It would have been approximately 65,600 m2 (706,000 sq ft) in area, nearly five times the size of the current terminal. This plan was also scrapped and a competition was held in hope of an even larger airport.
A competition for the final architectural and urban planning solution took place in August 2009, and the winner (Institut IGH) was declared at the beginning of October. This proposal, designed by Neidhardt architects of Zagreb, includes a retail component with stores, banks, cafes and restaurants. A new luxury hotel with direct underground links to the terminal is planned, directly in front of the new terminal. The new terminal will consist of glass walls and roof in a wavy facade. It will be built in three stages, the first stage being able to cater for over five million passengers. However this number will increase as phase two and three commence directly after. Initail construction is expected to cost €280 million. Air Force operations will move to the south end of the airport due to the construction. Meanwhile the old terminal will have a major face lift and minor expansion expected to cost 6 million euros.
On 12 April 2012, Aeroports de Paris received a 30 year concession of the airport from the Government of Croatia. The contract includes financing, designing and construction of a new passenger terminal. The construction works, lasting three years, will be carried out by Bouygues Bâtiment International in partnership with Viadukt. ZAIC will operate the entire airport for 30 years, including the runways, the current passenger terminal during the entire construction period, the new terminal, the cargo terminal, car parks and future property developments. The concession contract involves a total investment of €324m (£259m): €236 million for the design and construction of the new terminal and €88 million for operation of all airport infrastructure for the entire period of the concession.
Accompanying the terminal will be a second parallel runway. There will also be a new rail line alongside the Eastern bypass of Velika Gorica (currently under construction), which extends from Zagreb across the Homeland Bridge completed in 2007. These elements will create an entirely new east entrance into the city adding to the one via D408 state road. The airport is being built in such manner that more expansions can be conducted easily if needed. British Airways have announced that they will start services to the airport from London Heathrow.
Construction on the new terminal should start in early September 2013, and should be completed by mid to late 2016. According to architectural plans, the main terminal building will be 144x133m with the roof having a slightly larger footprint of 155x165m, with piers extending to a maximum of 670m width with 12 passenger boarding bridges as part of the phase 1, with phase 2, 350m extension to the right pier will be made adding additional 6 passenger boarding bridges. Total size of the terminal once completed will be around 72,500 square meters, excluding future extensions and add-ons.
As part of eco friendly approach the new terminal will also initially include 8500 square meters of solar panels on its roof, which should provide around 10-15% of Terminal's energy requirement, wind turbines could also be installed at some point.