We present APEX submillimeter lightcurves for about 40 Fermi blazars obtained over 3.5 years within the F-GAMMA monitoring program. Variability properties are described and compared with those obtained at longer cm to mm wavelength bands. A detailed cross correlation analysis implies a stronger and more direct correlation of submillimeter variability with gamma-rays than is the case at longer wavelengths. The correlation properties for different blazar types and for different source parameters are presented and discussed. A direct light curve analysis of flares observed in the two spectral bands is also made, in particular to study systematic patterns and their timing during flare onsets.