This is close to the end or the start (Depending where you begin) - of the Queen Charlotte Track.
Park your car near the Outward Bound School and begin walking along the track. Easy walk for about 20 minutes and you come to Davies bay. Dogs allowed as far as Davies bay - must be on a lead.
This can be a high muggle area so stealth may be required.
Cache is off the ground - so shouldn't be disturbed by an extra high tide.