Austroboletus subflavidus is a species of bolete fungus in the family Boletaceae. It is found in eastern North America, where it fruits near oak and pine trees. Originally described as a species of Tylopilus by American mycologist William Murrill in 1938, it was transferred to the genus Austroboletus by Carl B. Wolfe in 1980. The fruit body has a white to yellowish convex to flattened cap measuring 3– in diameter. The pores on the cap underside, which measure about 1 mm wide, are initially white to grayish before becoming pinkish. The coarsely reticulate and pitted stipe measures 4.5– long by 0.7–. The spore print is reddish brown; spores are spindle-shaped (fusoid) with dimensions of 15–20 by 6–9 μm.