1800–1899
- january 28, 1806 — neptune enters sagittarius.
- april 7, 1806 — neptune retrograde returns to scorpio.
- november 21, 1806 — neptune enters sagittarius.
- july 11, 1807 — neptune retrograde returns to scorpio.
- september 12, 1807 — neptune enters sagittarius.
- february 5, 1820 — neptune enters capricorn.
- june 2, 1820 — neptune retrograde returns to sagittarius.
- december 6, 1820 — neptune enters capricorn.
- february 13, 1834 — neptune enters aquarius.
- july 31, 1834 — neptune retrograde returns to capricorn.
- december 17, 1834 — neptune enters aquarius.
- april 26, 1847 — neptune enters pisces.
- july 12, 1847 — neptune retrograde returns to aquarius.
- february 18, 1848 — neptune enters pisces.
- october 15, 1848 — neptune retrograde returns to aquarius.
- december 6, 1848 — neptune enters pisces.
- april 13, 1861 — neptune enters aries.
- october 1, 1861 — neptune retrograde returns to pisces.
- february 14, 1862 — neptune enters aries.
- june 8, 1874 — neptune enters taurus.
- october 1, 1874 — neptune retrograde returns to aries.
- april 8, 1875 — neptune enters taurus.
- august 16, 1887 — neptune enters gemini.
- september 20, 1887 — neptune retrograde returns to taurus.
- may 26, 1888 — neptune enters gemini.
- december 27, 1888 — neptune retrograde returns to taurus.
- march 22, 1889 — neptune enters gemini.
1900–1999
- july 20, 1901 — neptune enters cancer.
- december 25, 1901 — neptune retrograde returns to gemini.
- may 21, 1902 — neptune enters cancer.
- september 23, 1914 — neptune enters leo.
- december 14, 1914 — neptune retrograde returns to cancer.
- july 19, 1915 — neptune enters leo.
- march 19, 1916 — neptune retrograde returns to cancer.
- may 2, 1916 — neptune enters leo.
- september 21, 1928 — neptune enters virgo.
- february 19, 1929 — neptune retrograde returns to leo.
- july 24, 1929 — neptune enters virgo.
- october 3, 1942 — neptune enters libra.
- april 17, 1943 — neptune retrograde returns to virgo.
- august 2, 1943 — neptune enters libra.
- december 24, 1955 — neptune enters scorpio.
- march 12, 1956 — neptune retrograde returns to libra.
- october 19, 1956 — neptune enters scorpio.
- june 15, 1957 — neptune retrograde returns to libra.
- august 6, 1957 — neptune enters scorpio.
- january 4, 1970 — neptune enters sagittarius.
- may 3, 1970 — neptune retrograde returns to scorpio.
- november 6, 1970 — neptune enters sagittarius.
- january 19, 1984 — neptune enters capricorn.
- june 23, 1984 — neptune retrograde returns to sagittarius.
- november 21, 1984 — neptune enters capricorn.
- january 29, 1998 — neptune enters aquarius.
- august 23, 1998 — neptune retrograde returns to capricorn.
- november 28, 1998 — neptune enters aquarius.
2000–2099
- april 4, 2011 — neptune enters pisces.
- august 5, 2011 — neptune retrograde returns to aquarius.
- february 3, 2012 — neptune enters pisces.
- march 30, 2025 — neptune enters aries.
- october 22, 2025 — neptune retrograde returns to pisces.
- january 26, 2026 — neptune enters aries.
- may 22, 2038 — neptune enters taurus.
- october 21, 2038 — neptune retrograde returns to aries.
- march 23, 2039 — neptune enters taurus.
- july 16, 2051 — neptune enters gemini.
- october 23, 2051 — neptune retrograde returns to taurus.
- may 12, 2052 — neptune enters gemini.
- july 3, 2065 — neptune enters cancer.
- january 14, 2066 — neptune retrograde returns to gemini.
- may 2, 2065 — neptune enters cancer.
- september 1, 2078 — neptune enters leo.
- january 6, 2079 — neptune retrograde returns to cancer.
- july 3, 2079 — neptune enters leo.
- september 4, 2092 — neptune enters virgo.
- march 11, 2093 — neptune retrograde returns to leo.
- july 5, 2093 — neptune enters virgo.