A detailed structural investigation of a series of fluoride phosphate laser glasses with nominal composition 25BaF2-25SrF2-(30 - x)Al(PO3)3-xAlF3-(20 - z)YF3:zREF3 with x = 25, 20, 15 and 10, RE = Yb and Eu, and 0 ≤ z ≤ 1.0 has been conducted using Raman, solid-state nuclear magnetic resonance (NMR), and electron paramagnetic resonance (EPR) spectroscopies. The network structure is dominated by the preferred formation of aluminum-to-phosphorus linkages, which have been quantified by means of 27Al/31P NMR double-resonance techniques. The fluoride ions are found in mixed Al/Y/Ba/Sr environments accommodating the luminescent dopant species as well. The local environments of the rare-earth species have been studied by pulsed EPR spectroscopy of the Yb3+ spin probe (S = 1/2), revealing composition-dependent echo-detected lineshapes and strong hyperfine coupling with 19F nuclei in hyperfine sublevel correlation (HYSCORE) spectra consistent with the formation of Yb3+-F bonds. In addition, photoluminescence spectra of Eu3+-doped samples reveal that the 5D0 →7F2/5D0 →7F1 transitions intensity ratio, the normalized phonon sideband intensities in the excitation spectra, and excited state 5D0 lifetime values are systematically dependent on fluoride content. Altogether, these results indicate that the rare-earth ions are found in a mixed fluoride/phosphate environment, to which the fluoride ions make the dominant contribution. Nevertheless, even at the highest fluoride levels (x = 25), the data suggest residual rare-earth-phosphate coordination.