Stoneheart Sea

The Stoneheart Sea is a sea north of Miscellania within the Northern Ocean, between the Island of Stone and the Iceberg. A cluster of islands labelled "Here be penguins" is located here, indeed with penguins present.

Some fremennik shipwrecks can be found far to the north.

Charting activates reward various amounts of Sailing experience, with significant bonus experience for completing every charting task in any given sea or ocean.

Level	Type	Task	Sea	Ocean	Location	Comp%
78	Crate	Find a Sealed crate in the far north of the Stoneheart Sea and sample the contents. Beware of Icy seas!	Stoneheart Sea	Northern Ocean	Map	12.9%
78	Generic	Find a shark corpse on a small island north west of Etceteria. Beware of Icy seas!	Stoneheart Sea	Northern Ocean	Map	13.1%
78	Weather	Help the meteorologist document the local weather on a small island south west of the Island of Stone. Beware of Icy seas!	Stoneheart Sea	Northern Ocean	Map	12.8%
78	Current	Test the currents west of the Island of Stone. Beware of Icy seas!	Stoneheart Sea	Northern Ocean	Map	12.8%
78	Spyglass	Use your spyglass to get a good view of the KGP training area from the west. Beware of Icy seas!	Stoneheart Sea	Northern Ocean	Map	12.9%
78	Diving	With help from a mermaid guide, document the water depth north of the Island of Stone. Answer to the riddle: Rain bow Beware of Icy seas!	Stoneheart Sea	Northern Ocean	Map	12.8%

• 20 March 2025 - 26 March 2025 (March 2025 Sailing Alpha)

• In the March 2025 Sailing Alpha, the area north of the Island of Stone was named "Mammoth Sea", but it was renamed in the June 2025 Sailing Beta. That name may have been a reference to RuneScape 3's Mammoth iceberg, located in the same area.