It is located on a narrow 2.5 km (1.6 mi) long sandspit that runs along the eastern side of the Avon Heathcote Estuary and west of the Pacific Ocean.

The area holds strong historical and cultural importance to the local Māori hapū, Ngāi Tūāhuriri, because the land and estuary provided a large amount of resources and seafood.

Southshore's population predominantly consists of European New Zealanders; its above-average housing costs and coastal setting attracts an older demographic to the area.

Notable people with connections to the suburb include the motorcycle speedway rider Ivan Mauger, the former deputy-mayor of Christchurch Peter Skellerup, and the former chairman of the Ngāi Tahu Māori Trust Tipene O'Regan.

[8] Prior to the 20th century the area was known locally to early European settlers as Sandhills Run, a name no longer in common usage.

There were many wharenui (the Māori term for a type of communal house) around the estuary, which were mainly built from raupō and other native trees.

[17][18] In the eighteenth century, Māori predominantly grew aruhe and kūmara in the sandy soil around the area of the Avon River / Ōtākaro.

In Southshore's early years, a local jogger presumably discovered a wharenui totem in the sand dunes near Tern Street, but others dispute this, as there is no documentation.

[20][21] There was a walking track from the fortified settlement of Kaiapoi Pā towards South New Brighton, and onwards further to the area now known as Southshore and beyond across the Avon Heathcote Estuary to the Banks Peninsula.

[22][23] There was also a sand dune walking track called Pohoareare, between the Ōpāwaho settlement to New Brighton and onwards to Te Kōrero Karoro.

[27] A local resident between 1940 and 1945 reported that the New Zealand Army bulldozed the sandhills and removed the vegetation around Caspian Street to set up a position for defence.

This work possibly lowered the land surface here, and the area is prone to extensive flooding by estuary and sea waters.

In 1958, another local resident filled a marshy area in use of six sections before building at the Caspian Street and Estuary Road intersection.

[38][39] Sand from the mouth of the Waimakariri River was carried southward the east coast of the South Island, and built up along the coastline of what is now Christchurch, progressively forming what is known as the Southshore Spit.

[46][47][c] The western side of the Southshore spit commands views of the estuary, other eastern suburbs of Christchurch, and parts of the Hillsborough spur.

Historically, coastal dunes provided important resources for local Māori, including weaving materials from made the natural sand binder pīngao.

Introduced plants such as marram grass were rebuilt and stabilised when the settlers realised the dunes were a useful coastal protection resource.

[49][50] As of 2024[update], the Christchurch City Council has approved NZ$12,500,000 in funding to address issues related to erosion and flooding in Southsore and South New Brighton.

Southshore's above-average housing costs, and the coastal setting of the suburb, attracted an older demographic to the area.

[62][63] The estuary side remained in the orange zone awaiting a decision whether it was financially worth repairing and rebuilding on that land due to the extensive damage caused by the two main shakes and aftershocks.

[67][68] Households which were committed to stay in Southshore, tended to disagree with the red-zoning scheme and frequently sought legal advice or geotechnical explanations for its implementation.

For other committed stayers, earthquake damage combined with the lack of amenities in the suburb had less impact on their dedication to the community of Southshore.

For example, a local farmer grazed livestock at the southern end of the spit before houses were built, and some people denied the bridge builders easy access through their land.

The name reportedly originates from Peter Skellerup, a former deputy-mayor of the city, who drove the road in its early years, describing it to his son as "travelling on a rocking horse" (before it was metalled and levelled).