You can reliably get Grand Soul Gems (and fill them with grand souls) in Oblivion from a mix of fixed locations, merchants, and high‑level creatures.

Fast answer: best places

If you just want a quick answer to “Oblivion where to get grand souls”:

  • Loot display cases in Mages Guilds , especially Chorrol and the Arcane University (Imperial City).
  • Buy Grand Soul Gems from Aurelinwae or Calindil at the Mystic Emporium (Imperial City Market) and from other Mages Guild spell merchants.
  • Explore specific dungeons like Crayfish Cave, Drakelowe, Nornal, Squandered Mine, Swampy Cave for guaranteed Grand Soul Gems.
  • Trap grand souls from strong creatures (Daedra like Xivilai, high‑level monsters) using Soul Trap into empty Grand Soul Gems.

Static “guaranteed” Grand Soul Gem locations

These places almost always have Grand Soul Gems waiting in containers or display cases, usually behind Very Hard locks.

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Location Where exactly How many
Arcane University (Imperial City) Arch‑Mage’s Lobby display cases, and a display case in the Mage’s Quarters (Very Hard locks). About 4 total (3 in lobby, 1 in quarters).
Chorrol Mages Guild Two display cases on the main floor, one to the left after entering (Very Hard locks). Up to 5 total across both cases.
Crayfish Cave Along the Corbolo River to the south‑southeast; search deeper chambers and chests. 1 Grand Soul Gem.
Drakelowe Basement reached via the trapdoor hidden in the fireplace. 1 Grand Soul Gem.
Nornal (Ayleid ruin) West of Drakelowe, near “The Nibenay Basin” map text; behind/near a lich in the ruins. 1 Grand Soul Gem.
Squandered Mine Northeast of Drakelowe; behind a secret door on the lowest level (Wind Holes), guarded by undead. 1 Grand Soul Gem.
Swampy Cave Dry Rock Run section; chest in large room with two swamp trolls (version‑dependent spawn).1 Grand Soul Gem (console versions).
These static spots are ideal if you’re doing quests like **“Vampire Cure”** that explicitly ask for multiple Grand Soul Gems, because you can plan a little loop and come out with several at once.

Buying Grand Soul Gems

If you don’t want to dungeon‑crawl, buying them is consistent, especially once you have some gold.

  • Imperial City – Mystic Emporium (Market District)
    • Aurelinwae and Calindil can stock Grand Soul Gems. Their inventories refresh after waiting in‑game (typically 3 in‑game days; some guides suggest waiting 7 to be safe).
  • Mages Guild Halls across Cyrodiil
    • Most guild halls have at least one merchant who can sell a Grand Soul Gem in their magical goods stock.
* You can also pickpocket these gems from the same merchants if you’re playing a stealthy character.
  • Quest rewards / quest locations
    • During the “Sins of the Father” quest, several Grand Soul Gems can be obtained, often already filled, though these may not all be empty for enchanting.

If merchant inventories are empty, wait somewhere for several days, then check again until Grand Soul Gems show up.

Getting actual grand souls (creatures to farm)

A Grand Soul Gem is only half the equation—you need grand‑level souls to make the most potent enchantments.

Common ways to get grand souls:

  • Fight high‑level Daedra and monsters
    • Creatures like Xivilai have grand souls that can be captured in standard Grand Soul Gems (no black gem needed), unlike some humanoid enemies that require Black Soul Gems.
* Xivilai appear in **Oblivion Gates** and later‑game Daedric encounters; with high Conjuration, you can even summon them and Soul Trap your own summons.
  • Level up, then revisit dangerous areas
    • Many grand‑soul creatures are level‑scaled. The higher your level, the more often they spawn in deep dungeon sections or Oblivion worlds.
  • Use Soul Trap tactically
    • Cast Soul Trap on a grand‑soul creature and kill it before the effect expires while carrying empty Grand Soul Gems. The captured souls then give you the highest charge value for enchanting (up to 1600 for a filled grand gem).

An example loop: buy or steal several empty Grand Soul Gems in the Imperial City, enter an Oblivion Gate, cast Soul Trap on Xivilai or other grand‑tier creatures, and exit with multiple fully charged gems ready for enchanting.

Extra notes and small tips

  • Lockpicking : many of the best static spawns are behind Very Hard locks, so Invest in Security or use Open Very Hard Lock spells/scrolls.
  • Console / ID (PC): the Grand Soul Gem item ID (empty and filled variants) is documented, with the grand‑filled form listed as a specific code (e.g., 000382DF for a grand‑filled variant in some references), useful if you are modding or testing.
  • Version quirks : on some platforms (PS3 GOTY, certain console versions), a few of the “empty” static gems may already be filled, which is great for charging gear but less useful if you specifically need empty gems for a quest requirement.

TL;DR: For “Oblivion where to get grand souls,” hit Chorrol Mages Guild and the Arcane University display cases, buy Grand Soul Gems at the Mystic Emporium and Mages Guilds, then fill them by Soul Trapping high‑level Daedra like Xivilai in Oblivion Gates.

Information gathered from public forums or data available on the internet and portrayed here.