605 Area Code — Sioux Falls, South Dakota

Where is area code 605?

The 605 area code is a North American Numbering Plan geographic code serving Sioux Falls and the surrounding South Dakota (statewide) region in South Dakota. Assigned by the North American Numbering Plan Administration in 1947, it currently serves approximately 900,000 residents on the Central Time (CT) (UTC-6 / UTC-5 DST). It is a single-coverage area code with no overlays.

Cities served by the 605 area code

The 605 area code covers 5 major cities and towns across the South Dakota (statewide) region:

Businesses across Sioux Falls and surrounding cities use 605 numbers to project local presence and lift call answer rates. Industry studies of local presence dialing consistently report answer-rate gains of 20–40% over toll-free or out-of-area numbers — a caller ID that matches the recipient's region looks familiar and gets picked up.

605 area code time zone and business hours

The 605 area code is in the Central Time (CT) zone (UTC-6 / UTC-5 DST). Standard business hours in 605 run 9 AM to 5 PM CT.

If you're calling into 605 from a different time zone, factor in the offset. For example, an Eastern Time business calling 605 at 9 AM ET reaches Sioux Falls at 8 AM CT — likely outside standard business hours.

History of the 605 area code

The 605 area code was one of the original 86 area codes assigned in 1947 when the North American Numbering Plan was first deployed. It remains a single-coverage area code with no current overlay assignments.

Is the 605 area code safe? Spam and scam calls

605 is a legitimate geographic area code for Sioux Falls — it is not a scam code or a premium-rate prefix, and a call from a 605 number is most likely a genuine local caller. The risk is not the area code itself but a tactic called neighbor spoofing: scammers fake their caller ID so an unwanted call appears to come from your own area code, because people answer familiar numbers more readily.

If you get an unexpected 605 call, a few signals point to a likely scam — a pre-recorded message, urgent pressure to act now, a demand for payment by gift card or wire transfer, or anyone asking for passwords, Social Security, or account numbers. Let suspicious calls go to voicemail, never share personal information, and report fraud to the FTC at reportfraud.ftc.gov. The FCC consumer guide on spoofing explains your rights under the Truth in Caller ID Act. A real Sioux Falls business will leave a clear voicemail and will not pressure you.

US carriers verify caller ID with the STIR/SHAKEN framework, which flags many spoofed numbers as "Spam Likely" before they ring. DialPhone 605 numbers are registered for STIR/SHAKEN attestation, so calls from your business are verified as genuine and reach customers without a false spam label. See the DialPhone guide to VoIP security for more.

Why get a 605 area code number for your business?

Getting a 605 number gives your business three measurable advantages over a toll-free or out-of-area number:

1. Local trust signal. Customers in Sioux Falls recognize 605 as their home area code. Caller ID matching builds immediate credibility for service businesses, sales outreach, and patient communication.
2. Higher answer rate. Calls from a familiar local area code are answered far more often than unknown or toll-free numbers — industry measurements of local presence dialing put the lift at 20–40%, which matters most for outbound sales, appointment confirmations, and time-sensitive service callbacks.
3. Targeted marketing. Businesses serving Sioux Falls and the broader South Dakota (statewide) can advertise a local number across print, radio, billboards, and digital channels for higher conversion than a national 800 number.

For businesses in Sioux Falls and surrounding cities, top industries that benefit from local 605 presence include Professional Services, Healthcare, and Retail. DialPhone's AI receptionist is available for every 605 number — never miss a call, even after standard business hours.

How to get a 605 area code number

Setting up a 605 business number with DialPhone takes under 10 minutes:

1. Sign up for a DialPhone plan. Choose any plan starting at $24/user/month. Free 14-day trial, no credit card required.
2. Search available 605 numbers. Filter the DialPhone number inventory by area code, city, or pattern.
3. Choose your number and configure. Assign your new 605 number to a user or team, set up call routing, voicemail, AI receptionist, and business SMS.
4. Port your existing number (optional). Already have a 605 number? Free number porting in 2 to 5 business days with zero service interruption.

New to local numbers? The complete guide to getting a local phone number covers choosing the right area code, porting an existing line, and avoiding spam flags.

AI receptionist for 605 area code businesses

Every DialPhone 605 number includes optional AI receptionist coverage, available 24/7. The AI handles calls when your team is unavailable — answering common questions, booking appointments, routing urgent callers to on-call staff, and capturing voicemail with full transcription and intent tagging.

For businesses in Sioux Falls that handle high call volume, run extended hours, or need bilingual support (especially valuable in service areas with diverse customer bases), the AI receptionist reduces voicemail backlog and improves first-call resolution.

Nearby area codes

Related area codes in South Dakota and the Central Time (CT) region:

• 205 area code — Birmingham, Alabama
• 210 area code — San Antonio, Texas
• 214 area code — Dallas, Texas
• 217 area code — Springfield, Illinois
• 218 area code — Duluth, Minnesota
• 219 area code — Hammond, Indiana

All South Dakota area codes → · Browse all US area codes →

More area codes: ← 603 Manchester · 606 Ashland →

How We Tested

DialPhone re-verifies every area code page every 90 days. Area code geography, timezone, and overlay data come from the official North American Numbering Plan Administration (NANPA) database. Pricing reflects the published DialPhone plan tiers — see the pricing page for current details. Number availability varies; check the DialPhone signup flow for live inventory in the 605 region.

What We Don't Like

• Number availability is finite. Popular Sioux Falls area codes can be inventory-constrained — request specific vanity patterns early.
• Porting timing varies. Most 605 ports complete in 2-5 business days; complex multi-line legacy contracts can take 7-10.
• HIPAA tier required for healthcare. The Core $24 plan doesn't include a BAA — healthcare users need Advanced ($34) or above.