According to
My Entertainment World, Transformers 5 will
begin principle photography sometime in May. Not sure really sure about the accuracy of the site's info but that date is pretty predictable considering the last three films all started filming in late April or mid May the year before intended release date of the movie and continued filming through the summer at a variety of locations. So in this case the plan is probably start filming from May to August or September and then post production through to May or June 2017.