Vertex Pharmaceuticals has finally planted its flag in Boston’s Seaport District, with a shiny new logo adorning the exterior of its new headquarters.

The two 18-story buildings totaling 1.1 million square feet were originally slated for completion in late 2013, but the big pharma giant has yet to begin occupying the property at Boston’s Fan Pier. That’s expected this coming spring..

The two towers being leased by Vertex are the second and third major structures on developer Joe Fallon’s waterfront land. The completed 21-acre Fan Pier development complex is expected to contain eight buildings with office space, residences, retail space and hotel rooms, as well as a park and marina.

Fallon broke ground in October on a 14-story luxury residential tower at Fan Pier, a 118-unit building called Twenty Two Liberty. That project is one in a flurry of office, residential and retail projects planned or under construction in the city’s Seaport.