By the time of its September 23 opposition, Neptune is rising in the east at sunset and visible all night. Opposition for Neptune will fall at 13 UTC on September 23, 2025 (8 a.m. CDT). Distance from Earth: Neptune is at its shortest distance from Earth for 2025, 240 light-minutes or 28.9 AU from Earth on September 23. 2024 Neptune opposition – September 202025 Neptune opposition – September 232026 Neptune opposition – September 25Neptune events in 2025March 20, 2025: Neptune at solar conjunctionJuly 5, 2025: Neptune begins retrograde motionSeptember 23, 2025: Neptune at oppositionDecember 11, 2025: Neptune ends retrograde motionYou need optical aid to see NeptunePlanets are brightest when at opposition. Bottom line: Neptune at opposition – when it’s 180 degrees from the sun on the sky’s dome – comes early on September 23, 2025.