Vegetation structure and soil properties were measured on a sandbar, a three year old sandbar emergent marsh (SEM), and five mature Spartina alterniflora Loisel marshes located near the mouth of the Altamaha River (Georgia, USA) to determine how quickly tidal marsh vegetation and soils develop during primary succession. Those data were compared to published data collected from young (10–16 yr old) natural marshes in Virginia and young (1–28 yr old) constructed marshes in North Carolina to determine if the rate of ecosystem development is similar among tidal marshes of the southeastern US coast. Within three years of emergence, aboveground biomass of SEM was comparable to mature marshes in the area, although stem height and density were distinctly different as the SEM contained more stems that were of shorter height than mature marshes. Following colonization by vegetation, soil properties (0–30 cm) of SEM had begun to differentiate from sediments of the sandbar. Surface (0–10 cm) and subsurface (10–30 cm) soil bulk density was less, and organic carbon (C), nitrogen (N), and percent silt (0–10 cm) were greater in sediments of SEM than in the sandbar. Even so, soils of SEM contained less organic C, N, silt, and clay than mature marshes. However, accumulation rates of organic C (260 ± 40 g m⁻² yr⁻¹) and N (11 ± 3 g m⁻² yr⁻¹) in soils of SEM was 5 to 7 times greater than in mature marshes (35 ± 4 g C m⁻² yr⁻¹, 2 ± 0.2 g N m⁻² yr⁻¹). Trajectories of development for soil organic C and N pools were similar for our SEM, young natural S. alterniflora marshes in Virginia, and young constructed S. alterniflora marshes in North Carolina suggesting that soil development proceeds at similar rates for tidal marshes along much of the southeast US coast.