Predicting heat flow in constrain modeling of a petroleum system in the Red Sea is a significant exploration challenge. In this study, we developed an integrated workflow to utilize seismic, magnetic and gravity data in the offshore Jazan area of the Red Sea to build a crustal model and to identify crustal type. Depth to Curie temperature was estimated from magnetic data and used together with thermal properties of the rocks to predict present-day heat flow for the interpreted crustal model. The predicted heat flow shows a generally increasing trend toward the rift axis due to an elevated asthenosphere boundary that is consistent with a thinned crust model. The model of thinning continental lithosphere and predicted heat flow derived from the integrated workflow provides valuable constraints to reduce the uncertainties in basin modeling.