The district known as Seaside grew and developed as a result of the shipping trade that used the Llanelli foreshore known as ‘The Flats’. The predominant cargo of this trade was the export of local coal from mines situated in close proximity to this shipping place; coal originally taken down to the Flats in sacks carried by horses and pack mules. As early as 1566, it was recorded that ten tons of coal was shipped from Llanelli to Bideford on board the ship ‘Le Saviour de Bideford’. The growth of Seaside as a community can be attributed to the arrival of the entrepreneurs Alexander Raby and Charles Nevill. In the late 18th and early 19th Century Raby’s trade was predominantly concerned with iron and Nevill’s with copper. As well as their manufactured goods, both industrialists exported coal from the docks they had constructed in the locality. Llanelli at this time (1807) was said to be ‘chiefly inhabited by miners and sailors’. Early 19th century plans show Seaside with just a few houses scattered around the Flats, the Carmarthenshire Dock and the Copperworks. Some of these houses that once stood in Bryn Road and Nelson Terrace were, according to an old Seasider “as being of the non-staircase type! The bedrooms like many other dwellings of that period were approached by means of a ladder. When retiring for the night the more timid person made sure no one would enter by that way when the family were asleep, for on entering the bedroom, the last one would pull up the ladder through the aperture, then placing it across the entrance. This mode of retiring for the night was common in old thatched cottages in and around Llanelli. These dwellings were demolished before the end of the nineteenth century”.
By 1850 Seaside had grown in to a considerable community occupied by workshops, houses, pubs, taverns, shops, chapels and a Customs House. It was described in an official report published in 1856 as “A cottage population of about 2000 persons. The houses are for the most part built on a copper slag bank, which forms a dry foundation, and raises the general level above the high water mark”. By 1880 it had become a proud community of its own, virtually separate from the town of Llanelli.