Area code 210 opened in November 1992, when the 512 area of south Texas was split in two. A second split in July 1997 left 210 with the San Antonio metropolitan area and moved the outer areas to 830 and 956. Since October 2017, overlay code 726 has served the same territory alongside 210.
Quick answer
- 210 serves San Antonio, Texas. It opened in November 1992 (FCC), split from 512 (Bellcore letter published by NANPA).
- In July 1997, 210 was divided into three areas. San Antonio kept 210, 830 took the northern section, and 956 took the southern section (NANPA planning letter).
- 726 is an overlay on the same area. The PUC approved it on July 20, 2016, and 726 numbers could be activated from October 23, 2017 (NANPA).
- Local calls require ten digits, mandatory since September 23, 2017 (NANPA). Dial 1 plus ten digits for toll calls.
The essentials
210 area code: quick facts
| Area code | 210 |
| Coverage | San Antonio area: almost all of Bexar County and small parts of Atascosa, Comal, Guadalupe, Medina, and Wilson counties (PUC), shared with 726 |
| State | Texas |
| Time zone | Central Time (CT) |
| Opened | November 1992, split from 512 |
| Splits from 210 | 830 and 956, July 1997 |
| Overlay code on the same territory | 726 (activation from October 23, 2017) |
| Dialing | 10 digits for local calls: 3-digit area code plus 7-digit number |
| Country code | +1, the country code for the North American Numbering Plan |
How 210 became San Antonio's code
- November 1, 1992: The 512 area of south Texas is split, and 210 is introduced. A Bellcore industry letter, now published by NANPA, says Southwestern Bell reported "substantial telephone number growth in south Texas." The new 210 area included the San Antonio and Brownsville LATAs, while the Austin and Corpus Christi LATAs stayed in 512. Either code worked during a permissive dialing period that ended on May 2, 1993. The FCC lists 210 as opened in November 1992.
- December 1996: NANPA's index of planning letters lists PL-025, "Declaration of jeopardy situation in NPA 210 (Texas)." The letter itself was not reviewed for this guide, only its listing.
- January 22, 1997: NANPA planning letter PL-NANP-035 announces that 210 will be divided into three areas, with two new codes, 830 and 956.
- July 7, 1997: The split takes effect at 12:01 a.m. EDT. The San Antonio metropolitan area keeps 210. Permissive dialing for the new codes ends on October 6, 1997. The FCC lists 830 and 956 as opened in July 1997.
- July 20, 2016: The PUC approves an all-services overlay as the relief method for 210, in Project No. 45224 (NANPA planning letter PL-495).
- July 21, 2016: The PUC announces that NANPA has assigned 726 as the overlay code. The release says the remaining 210 numbers were forecast to last until early 2018.
- March 25, 2017: Permissive 7-digit and 10-digit local dialing begins.
- September 23, 2017: Mandatory 10-digit local dialing starts at 12:01 a.m. Central Time.
- October 23, 2017: The earliest date that 726 numbers can be activated. NANPA calls this the in-service date of the new code, and the FCC lists 726 as opened in October 2017.
Where area code 210 is used
The PUC's July 2016 release says the 210 area includes almost all of Bexar County and small portions of Atascosa, Comal, Guadalupe, Medina, and Wilson counties. NANPA's planning letter for the 726 overlay describes the same area as the greater San Antonio area, including all or parts of Alamo Heights, Balcones Heights, Castle Hills, Cibolo, Converse, China Grove, Elmendorf, Fair Oaks Ranch, Garden Ridge, Grey Forest, Helotes, Hill Country Village, Hollywood Park, Kirby, Leon Valley, Live Oak, Olmos Park, Saint Hedwig, Schertz, Selma, Shavano Park, Terrell Hills, Universal City, Von Ormy, and Windcrest.
The PUC's list of 210 prefixes, in an archived 2025 copy that reflects NANPA data through November 2023, shows 799 prefixes, all listed under the San Antonio rate center. The 726 list shows 80 prefixes, also under San Antonio. A rate center is a billing area, not a boundary, so a city name in the list does not mark where numbers are used. Confirm a specific address with your phone provider.
Why 210 added a code
210 has needed relief twice. In 1997, NANPA said Southwestern Bell reported "substantial number growth in the San Antonio area of Texas," which led to the split into 210, 830, and 956. NANPA's planning letter index also lists a 1996 jeopardy declaration and 1997 conservation procedures for 210, which are steps taken when codes run short.
In 2016, the PUC said the new code was "needed to handle regional growth combined with added demand for wireless phone numbers and business landlines." This time, the relief method was an overlay, not a split. Under an overlay, current 210 customers keep their numbers, and new customers can be assigned either 210 or 726.
NANPA's April 2026 analysis projects that the 210/726 area will run out of numbers in the first quarter of 2072, based on data as of March 1, 2026. The previous analysis (October 2025) gave the third quarter of 2069, so the estimate moved 10 quarters later. Forecasts move from one analysis to the next, so treat the date as an estimate.
Neighboring area codes in the San Antonio area
The table shows how each code relates to 210, based on the NANPA, PUC, and FCC sources in this guide. Other codes serve areas outside the sources checked, so the table does not claim to show every neighbor.
| Code | Where it applies | Relation to 210 |
|---|---|---|
| 210 | San Antonio metropolitan area | Opened 1992 |
| 726 | Same area as 210 | Overlay, numbers from October 23, 2017 |
| 512 | Austin LATA and Corpus Christi LATA after 1992 | Parent code; 210 split from it in 1992 |
| 830 | All or part of 34 counties north of the 1997 line, including Uvalde, New Braunfels, Fredericksburg, and Kerrville | Split from 210 in July 1997 |
| 956 | Seven-county area including Laredo, Brownsville, and McAllen | Split from 210 in July 1997 |
The 830 and 956 descriptions come from the 1997 planning letter and describe the plan at that time. Later changes to 512 and the Corpus Christi area are outside the scope of this guide.
Code family: splits and overlays
NANPA lists these codes as related to 210, with the date each entered service. A split moves part of a code's area to a new code. An overlay adds a code to the same area.
| Code | Relation to 210 | In service |
|---|---|---|
| 512 | 210 was split from this code | January 1, 1947 |
| 210 | This code | November 1, 1992 |
| 830 | Split from 210 | July 7, 1997 |
| 956 | Split from 210 | July 7, 1997 |
| 726 | Overlay: shares 210's area | October 23, 2017 |
Source: NANPA NPA report, file dated October 26, 2026.
The overlay code that shares 210's territory
An overlay adds a new area code to the same geographic area, so existing numbers do not change. NANPA's planning letter says the new 726 code "will serve the same geographic area currently served by the existing 210 NPA."
- 726 (approved July 20, 2016; numbers from October 23, 2017): the only overlay on 210 in the sources checked.
Because the codes overlap, two neighbors on the same street can have different area codes. The PUC says current 210 customers keep their 210 numbers, and new customers could be assigned either 210 or 726.
Time zone and daylight saving time
Area code 210 uses Central Time. The tz database lists America/Chicago as "Central (most areas)". Federal rules for the boundary between the Central and Mountain zones (49 CFR 71.7) run along the east line of Hudspeth County in far west Texas, and Bexar County lies east of that line.
NIST says daylight saving time begins at 2:00 a.m. on the second Sunday of March and ends at 2:00 a.m. on the first Sunday of November. The NIST page lists Hawaii, American Samoa, Guam, Puerto Rico, the Virgin Islands, and Arizona as places that do not observe it, and Texas is not on that list. In 2026, NIST gives March 8 and November 1 as the change dates.
When it is 10:00 a.m. in San Antonio
| Where you are | Local time |
|---|---|
| Eastern Time | 11:00 a.m. |
| Central Time | 10:00 a.m. |
| Mountain Time | 9:00 a.m. |
| Pacific Time | 8:00 a.m. |
These differences hold all year, because the Eastern, Central, Mountain and Pacific zones change clocks on the same dates. Arizona does not observe daylight saving time (NIST), so an Arizona clock matches Mountain Time in winter and Pacific Time in summer. A 210 number does not prove the person you are calling is in the Central zone, so use the time where the person actually is.
How to dial a 210 number
North American numbers have three parts: a country code, a three-digit area code, and a seven-digit local number. NANPA says the ITU assigned country code 1 to the NANP area. NANPA's planning letter for 726 sets the dialing plan for 210 and 726: 10 digits for local calls, 1 plus 10 digits for toll calls, and 0 plus 10 digits for operator-assisted calls such as collect or credit card calls.
This is a change from 1992, when the Bellcore letter said local calls inside 210 would be dialed with seven digits. The PUC's 2016 release says all customers would be required to dial 10 digits for all local calls and 11 digits for long distance.
From another country: dial +1 210 followed by the seven-digit number. Country code 1 is assigned to the North American Numbering Plan (NANPA).
Can you text a 210 number? The area code alone does not tell you. Whether a number can receive text messages depends on the number type, the carrier and how the number is registered.
Caller ID and scams with a 210 number
The FTC warns that "Scammers can make any name or number show up on your caller ID." That is called spoofing. Scammers can also match the first six digits of your own number, which the FTC calls neighbor spoofing.
- If you pick up and do not recognize the caller, the FTC advises that you hang up.
- Letting an unknown call go to voicemail is one option.
- The FTC says call blocking is your best defense against unwanted calls.
The sources checked do not say that 210 numbers are targeted more than others. A 210 number shows the code that was assigned, not who is calling or where they are. Because 726 shares the same area, a 726 caller can be just as local as a 210 caller.
Calling into the 210 area as a business
The rules for a business call depend on where the person you are calling is, not on the area code of their number. Numbers move between providers and phones travel, so a 210 number does not tell you which state's rules apply or what the local time is. NANPA lists the San Antonio area in the Central time zone, but the person who answers may be anywhere.
- Calling hours. The FCC rule at 47 CFR 64.1200(c)(1) bars telephone solicitations to a residential subscriber before 8 a.m. or after 9 p.m., measured as "local time at the called party's location." The FTC's Telemarketing Sales Rule, 16 CFR 310.4(c), sets the same 8:00 a.m. to 9:00 p.m. window by the local time at the called person's location.
- Do Not Call. Residential numbers listed on the National Do Not Call Registry are covered by 47 CFR 64.1200(c)(2).
- State rules. Texas and other states may add their own rules. This guide does not summarize state law. Check with a lawyer or the state attorney general before you run a calling campaign.
This is general information, not legal advice.
Related reading: Do Not Call compliance, predictive dialer compliance in 2026, and STIR/SHAKEN caller ID authentication.
Choosing a 210 number for a business
210 is the long-standing San Antonio code, but the PUC says new customers could be assigned either 210 or 726. A new line may carry 726 instead of 210, and the area code does not show which part of the area the business is in.
Because the codes share territory, route calls by team or extension, not by area code. Ask your provider which code a new line gets, since that depends on its current inventory.
Whether a specific 210 number can be assigned to your business depends on your phone provider and its current inventory. This guide does not make claims about availability.
Important: Confirm availability with your provider before you plan a campaign or print a number on materials.
Before you use a 210 number
- Confirm the number is available from your provider, and get its terms in writing.
- Ask who owns the number and whether it can be moved to another provider if you switch.
- Confirm which area code your line uses. 210 and 726 serve the same area.
- Set 10-digit dialing for numbers in both codes before you go live, because local calls in the area have required 10 digits since September 23, 2017.
- Print the full 10-digit number with the area code, and update any equipment that stores numbers in 7-digit form.
- Route calls by team or extension, because 210 and 726 share one territory.
- Plan for caller ID. A 210 number does not prove who is calling, and neighbor spoofing copies the first six digits of your own number.
Frequently asked questions
Which area is the 210 area code for?
Area code 210 serves San Antonio, Texas. It was created in a split from 512 in November 1992. In July 1997 it was split again, keeping the San Antonio metropolitan area while 830 and 956 took the north and south. Since October 2017, overlay code 726 has shared the same territory, which the Public Utility Commission of Texas (PUC) describes as almost all of Bexar County and small parts of five nearby counties.
Is area code 210 running out of numbers?
Not soon, according to the latest projection checked. NANPA's April 2026 analysis projects that the 210/726 area will run out of numbers in the first quarter of 2072. That date moved 10 quarters later than the previous analysis, so treat it as an estimate. When 726 was approved in 2016, the PUC said the remaining 210 numbers were forecast to last until early 2018.
Do I need to dial 10 digits for a 210 number?
Yes, for local calls. NANPA says mandatory 10-digit local dialing started in the 210 and 726 area at 12:01 a.m. Central Time on September 23, 2017. Local calls use 10 digits, and toll calls use 1 plus 10 digits.
Does a 210 number mean the caller is in San Antonio?
Not always. The FTC says scammers can make any name or number show up on caller ID, and neighbor spoofing matches the first six digits of your own number. A 210 number shows the code that was assigned, not who is calling or where they are.
What time zone is area code 210 in?
Central Time. The tz database lists America/Chicago as "Central (most areas)", and the federal rule for the Central and Mountain zone boundary runs through far west Texas. Daylight saving time starts at 2:00 a.m. on the second Sunday of March and ends at 2:00 a.m. on the first Sunday of November (NIST).
What hours can a business call a 210 number?
For telemarketing calls to a residential line, the FCC and FTC rules set 8 a.m. to 9 p.m. in the local time of the person called. A 210 number does not show where that person is, so use the time where the person actually is. NANPA lists the San Antonio area in the Central time zone. States may add rules; this is general information, not legal advice.
Sources (17)
- Bellcore IL-92/03-068, Split of 512 (south Texas), 1992, NANPA planning letters
- PL-NANP-035, Split of 210 (Texas), January 22, 1997, archived copy, NANPA planning letters
- PL-495, NPA 726 to Overlay NPA 210 (Texas), August 23, 2016, NANPA planning letters
- PUC release, July 21, 2016, archived copy, Public Utility Commission of Texas
- PUC San Antonio area codes page, Public Utility Commission of Texas
- PUC area code 210 prefix list, Public Utility Commission of Texas
- PUC area code 726 prefix list, Public Utility Commission of Texas
- Numbering Resource Utilization in the United States, FCC, Table 6
- About NANPA, archived copy
- 2026-1 NPA Exhaust Analysis, April 2026, NANPA (archived copy)
- 1996, North American Numbering Plan Administrator (archived copy)
- 1997, North American Numbering Plan Administrator (archived copy)
- Phone Scams, FTC Consumer Advice
- That's not your neighbor calling, FTC Consumer Alert
- Daylight Saving Time, NIST
- tz database zone table
- 49 CFR 71.7, Boundary line between central and mountain zones