There are a number of high speed Internet providers in Rancho Santa Fe and surrounding areas.
If you live in the Covenant of Rancho Santa Fe (ie. you pay dues to the RSF Association), then by far the best option is RSF Connect run by Race Communications.
If you live in nearby Solana Beach (or by late 2021, Encinitas), then Ting Internet is your best choice.
Both these providers offer fiber optics to the home with 1 Gigabit/second Internet.
By mid to late 2021, Starlink should be offering high speed low latency Internet to residents around the Rancho region who do not have access to other high speed options.
RSF Connect provides gigabit Internet (1,000 Mbps) to all RSF Covenant residents over an all fiber optic network. It also provides phone service and the equivalent of satellite or cable TV.
When the fiber network was built in 2018/2019, residents were responsible for installing their own conduit from the street to their house. Your particular house may or may not have had this done (check with previous owner). Race Communications, the RSF Connect operator, will do this work for you for an installation cost that is often $1,000 to $2,000. In addition, you will need to wire up your house for robust WiFi. Click here to read an article that gives contact information for local technology integration companies that can co-ordinate this for you.
If you live in Solana Beach (and in Encinitas in mid to late 2021), then Ting Internet will be the most reliable and high performance Internet option. They deliver 1 Gbps Internet over a recently built all fiber to the home network. Ting will finish connecting intial Solana Beach customers in 2020 and 2021 while their Encinitas network starts being built.
While you do have other options in Solana Beach and Encinitas, they are based on legacy technology and won't be as fast, efficient or reliable as Ting's all fiber optic network.
If you live in an underserved community near Rancho Santa Fe, high speed Internet salvation might come from the sky for you in mid 2021. Starlink, a division of SpaceX, will be starting operations in 2021 delivering 100 Mbps links with decent latency times. Satellite Internet has traditionally been a last resort due to slow speeds and huge latency, but Starlink is a different breed. Instead of relying on geosynchronous satellites 22,000 miles away in high orbit, Starlink uses a large constellation of satellites in a very near 350 mile high orbit. They are worth a look if you have no good high speed wired options.
San Diego Broadband provides high speed consumer and business class Internet access via a dish antenna that can see line of site to one of two mountains in the region (Black Mountain and Lake San Marcos). Their consumer prices are competitive with other consumer offerings and they have "no data cap" business plans.
SD Broadband tops out at about 30 Mbps, so I would only look at them if you had no other high speed choices. But their service is good and the link is generally reliable.
Depending on where your house is located, you could get no Internet connectivity, 1-3 Mbps download (via copper DSL), or up to 25 Mbps download speeds (if they have installed fiber to the curb in your area).
Click here to visit the AT&T availability web site to determine what is offered at your house.