Sulfur solubility in magmas is known to strongly depend on such factors as melt composition, magma oxidation state (fO 2), P, and T. Unlike the more common magmatic volatiles (H 2 O, CO 2), sulfur can occur in a variety of forms, mainly controlled by magma oxidation state; the most important S-species in natural systems appear to be H 2 S, S 2 , and SO 2 as gas/fluid phase components, and S 2-, HS-, or SO 4 2-, as species dissolved in silicate melts. As a result of this complexity (and possible S-rich crystals), it is not always easy to interpret the significance of observed variations in S-emissions in active volcanic systems in terms of what is happening at depth. Furthermore, estimation of S-yields to the atmosphere in older volcanic eruptions requires accurate knowledge of not only how much S was in the pre-eruptive melt (e.g., via melt inclusions), but also an estimate of the mass and fugacities of sulfur species in any pre-eruptive magmatic fluid phase. We have conducted experiments on S-solubility in a sodic phonolitic melt composition (with, in wt% ~60 SiO 2 , 18.8 Al 2 O 3 , 10 Na 2 O, 5.5 K 2 O), at T= 930°C, P = 50-390 MPa, using mainly IHPV with controlled H2 fugacity and S fugacity roughly controlled by using samples with different amounts of S added as elemental S. Oxidation states range from approximately-3 to +3 log fO2 units relative to the NNO buffer. Depending on the amount of S added, the experiments range from nearly water saturated (low S added) to significantly H 2 O undersaturated (P(H 2 O) down to ~0.5*P total), with significant fugacities of H 2 S or SO 2 in the fluid phase, depending on experimental oxidation state. Sulfur solubilities in these alkali-rich phonolites are generally higher than those for dacitic to rhyolitic melts reported in other studies at similar fO 2 and fS 2 conditions. While previous studies have reported anhydrite stable in oxidized, S-rich andesitic to rhyolitic melts, in the studied phonolite we observe the stabilization of S-rich Sodalite (Haüyne) with up to ~12 wt% SO 3 at pressures up to 150 MPa, whereas at higher pressures the phonolitic melts coexist with an oxygen-rich Fe-SO immiscible liquid, but no anhydrite was observed. Additional work will help understand if Sodalite-Haüyne S (and Cl) contents in natural samples may be useful for estimating pre-eruptive S and Cl activities in magmas.