The best place to farm Hardened Tortoise Shell is Thousand Needles, where Sparkleshell Snapper (level 34-35) drops it at 30.0%. That is the vanilla 1.12 chance, not yet confirmed in Forever. 3 sources are ranked below by drop chance.
Best zones:

- Sparkleshell Snapper 82.8, 54.4
- Sparkleshell Tortoise 82.6, 54.7
- Sparkleshell Borer 72.4, 88.8
All sources, by drop chance:
| Source | Level | Zone | Spawns | Side | How | Drop% | Map |
|---|---|---|---|---|---|---|---|
| Sparkleshell Snapper(quest) | 34-35 | Thousand Needles | 32 | Drop | 30.0% | map | |
| Sparkleshell Tortoise(quest) | 30-31 | Thousand Needles | 28 | Drop | 30.0% | map | |
| Sparkleshell Borer(quest) | 32-33 | Thousand Needles | 6 | Drop | 30.0% | map |
Needed for:
Quests:
Drop% is the rate recorded in Forever once a source has been looted ten times; a greyed figure is the vanilla 1.12 chance from the world data (vanilla reference — from the 1.12 world data, not yet confirmed in forever). Spawns counts the source's spawn points in the world data. "Side" names which side can kill the NPC when the other finds it friendly. The lead picks the best chance among sources that are not a rare spawn and have at least three spawn points.