The work will improve the art and design department, renew the engineering facilities and library and create a modern refectory.
Energy efficient lighting and boilers are being installed to reduce costs.
At the end of the summer, the college will be given its own wind turbine which will be used to help train workers in the wind farm industry.
The work is set to be finished by the start of the September term.
Principal Simon Summers said: "This work will bring these facilities for students and teaching and learning right up to date.
"The changes are rapidly taking shape and we are looking forward to opening the new facilities at the start of next term.
"Each year we welcome 5000 students to Lowestoft College so we are pleased that we are able to continue to make improvements to the college."
The funding has been provided by University Campus Suffolk, the Local Strategic Partnership, the Skills Funding Agency and Lowestoft College.
Building work on an £1.3m project to improve Lowestoft College in Suffolk has got under way.