Optical absorption and fluorescence spectra in the visible spectral range were investigated for an Ho3+-doped fluorozirconate fiber. From the absorption spectrum, the Judd–Ofelt (J–O) intensity parameters, Ω2, Ω4, and Ω6, were calculated along with the spectroscopic parameters, including radiative decay rates (AJJ′), radiative branching ratios (βJJ′), and radiative lifetimes (τrad) for the main emission levels, including 5I7, 5I6, 5F5, 5F4+5S2, 5F3, and 3K7+5G4 of Ho3+ ions. The excited-state absorption (ESA) mechanism of blue diode-pumped visible emission for an Ho3+-doped fluorozirconate fiber was investigated for the first time under blue pumping at 44X nm. Emission bands originating from 3K7+5G4 levels at peak wavelengths of 579 and 680 nm show a two-step excitation mechanism. These two emissions are enabled by ESA for both 5I6 and 5I7 levels, and the process to the 3K7+5G4 levels after nonradiative decay from the 5G2 level is ESA from the 5I6 level, whereas the process to the 3K7+5G4 levels after nonradiative decay from the 3H6 level is ESA from the 5I7 level. It has been revealed that enhancement of visible emission was enabled by introducing the ESA at 440 nm in an Ho3+-doped fluorozirconate fiber under dual-wavelength pumping at 449 + 440 nm.