Which tarot card is Neptune?
Neptune is attributed to The Hanged Man, the twelfth Major Arcanum.
The Hanged Man
Upright: Pause, surrender, letting go, new perspectives
Reversed: Delays, resistance, stalling, indecision
Full The Hanged Man meaning →Why The Hanged Man carries Neptune
Another modern attribution — Neptune was found in 1846 — and another that has stuck because the fit is unusually good. Neptune governs dissolution, surrender, illusion and the loss of ordinary boundaries.
The Hanged Man hangs upside down from a living tree by one ankle, hands behind his back, with a halo around his head and an entirely calm expression. Nothing is being done to him that he is resisting. The card is about suspension accepted — giving up the usual position in order to see from another one.
Neptune rules Pisces, whose card is The Moon. The pair covers the planet's two faces: The Moon is Neptune as being lost, The Hanged Man is Neptune as letting go on purpose. Which one a spread means usually depends on whether the surrender was chosen.
The difficult register
The shadow is suspension that has become avoidance — waiting reframed as spiritual patience when it is simply not deciding.
A modern attribution, and why that matters
Neptune was identified in 1846, well after the tarot trumps were fixed, so this attribution is a modern graft onto an older system rather than something inherited from it. That is worth stating plainly, because correspondence tables tend to present all attributions with equal authority.
The Golden Dawn built its system on the seven classical planets and the twelve signs, which accounts for nineteen of the twenty-two trumps; the other three were given to the elements. Neptune's claim on The Hanged Man comes indirectly, through its modern rulership of Pisces. Before Neptune, Jupiter ruled Pisces, and some readers still work that way — which would put The Hanged Man in a Jupiterian rather than Neptunian register, and it reads quite differently.
A practical consequence: Neptune rules none of the thirty-six decans. The decan rulers cycle through the seven classical planets in Chaldean order, so the outer planets appear in the Major Arcana but never among the pips. Timing work with the decans is a classical-planet layer only.