Best ISP in South Carolina (SC) for 2026

Top ISPs in South Carolina at a glance

ISP breakdown

1. AT&T Fiber

AT&T Fiber offers symmetric plans up to 5 Gbps in select metros. A wired test should land within 5% of the plan tier. On gigabit+ plans, your computer's NIC and Ethernet cable become the bottleneck — CAT6 or better is required to see above 1 Gbps.

2. Spectrum

Spectrum (Charter) runs cable in 41 US states. Standard plans are 300/500/1000 Mbps download with 10–35 Mbps upload. A slow Spectrum test usually means a neighborhood congestion issue or an aging modem — the DOCSIS 3.0 modems the company still ships to some customers cap at ~400 Mbps real-world.

3. Xfinity

Xfinity (Comcast) is the largest US cable ISP. Download speeds are strong, but upload is typically 5–35 Mbps unless you are on a fiber or mid-split node. Peak-hour congestion on shared cable segments is the most common cause of slow Xfinity tests between 7–10 PM.

4. T-Mobile Home Internet

T-Mobile Home Internet is 5G fixed wireless — speeds swing widely based on tower load, distance, and time of day. Expect 100–300 Mbps down and 10–40 Mbps up under normal conditions. If tests drop below 30 Mbps at night, the local 5G tower is likely deprioritizing home-internet traffic.

How to choose the best ISP in South Carolina

1. Check address-level availability — plan tiers and technology (fiber vs cable vs DSL) depend on what infrastructure runs to your street, not just your ZIP code.
2. Prioritize fiber — symmetric speeds, no shared-node congestion, and consistent latency. If fiber is available at your address, it almost always beats cable at the same price point.
3. Compare upload, not just download — if you work from home, video call, or back up to the cloud, upload symmetry matters as much as download headline speed.
4. Test after installation — run a wired Ethernet speed test within the cancellation window (typically 14–30 days) to verify the line hits 80–95% of your plan tier.

Broadband landscape in South Carolina

South Carolina's broadband market is anchored by the Charleston, Columbia, and Greenville-Spartanburg metros, where competition between AT&T Fiber, Spectrum cable, and Xfinity provides solid urban connectivity. AT&T Fiber has been one of the most aggressive fiber builders in South Carolina, covering large portions of Columbia, Greenville, Spartanburg, and the Charleston metro including North Charleston and Summerville. Spectrum is the dominant cable provider across the Upstate and Midlands regions, while Xfinity (Comcast) serves the coastal markets around Charleston and Myrtle Beach. The Myrtle Beach corridor and Grand Strand have seen growing ISP competition as the region's population has surged with retirees and remote workers.

Rural South Carolina — particularly the Pee Dee region in the northeast, the Lowcountry outside Charleston, and the Savannah River corridor along the Georgia border — has significant broadband gaps. Many rural counties rely on legacy AT&T copper DSL that delivers 10–30 Mbps in practice, far below modern standards. The South Carolina Office of Regulatory Staff (ORS) oversees broadband grant programs and has directed BEAD funding toward rural counties including Marion, Dillon, Marlboro, and Allendale, which have some of the lowest broadband penetration rates in the state. Rural electric cooperatives such as Palmetto Electric and Tri-County Electric are active in building fiber to their member communities in areas where commercial ISPs will not invest.

What to watch out for in South Carolina

• AT&T fiber vs. legacy DSL — verify before signing up: AT&T markets both fiber-to-the-home and legacy copper DSL in South Carolina. In rural and smaller-town addresses, DSL is still common and frequently delivers only 10–30 Mbps despite being marketed at higher plan tiers. Always confirm the technology type is explicitly "AT&T Fiber" (FTTH) at your address before signing a contract.
• Spectrum and Xfinity upload caps affect remote workers: Both Spectrum and Xfinity cable plans cap upload at 10–35 Mbps on standard tiers. In a state with a growing remote-work population — particularly in the Charleston and Greenville markets — this ceiling is a practical limitation for video conferencing and cloud-based workflows. If AT&T Fiber is available at your address, its symmetric upload is a compelling differentiator.
• Myrtle Beach area has seasonal congestion: The Grand Strand and Myrtle Beach corridor experience significant population swings between summer and winter, with the tourist influx straining local cable network capacity during peak season (June–August). Residents on Xfinity cable in this area may notice speed degradation during peak summer months that is not present in other seasons.
• Pee Dee and Lowcountry rural areas are severely underserved: Counties like Marion, Dillon, Marlboro, Allendale, and Hampton have broadband access rates well below the state average. Legacy DSL is often the only wired option, and speeds of 10–20 Mbps are common. Starlink and T-Mobile Home Internet are the most practical paths to broadband-class speeds in these counties today.
• Rural electric co-op fiber is the best emerging option: Palmetto Electric, Tri-County Electric, and other South Carolina cooperatives are building fiber to their rural members using BEAD and USDA ReConnect grants. These networks deliver symmetric gigabit speeds but are not tracked by national ISP comparison tools — contact your electric cooperative directly for availability and timeline information.

Frequently Asked Questions

Is fiber internet available in South Carolina?

Yes, fiber is available across significant portions of South Carolina's major cities. AT&T Fiber covers large areas of Columbia, Greenville, Spartanburg, and the Charleston metro. Some smaller local providers and electric cooperative fiber networks are available in specific rural communities. For most rural South Carolina addresses, fiber is not yet available — but BEAD-funded projects are under development for underserved counties. Use AT&T's address checker and the SC ORS broadband map for current availability at your specific address.

Which ISP has the best rural coverage in South Carolina?

T-Mobile Home Internet is the most accessible rural option in South Carolina where 5G tower coverage exists, generally along I-26, I-85, I-95, and US-501 corridors. Starlink is the most reliable option for very remote Lowcountry and Pee Dee addresses where terrestrial options are limited. AT&T DSL covers most rural SC addresses but real-world speeds on aging copper are often disappointing. Rural electric cooperative fiber — where available — is the best rural option; contact Palmetto Electric, Tri-County Electric, or your local cooperative for availability in your area.

Run a speed test to check your current line

Already have one of these ISPs? Run a free speed test to see what your line actually delivers — and compare it to your plan tier.