William Thomas Harless, M.D.
Internal Medicine Physician · San Diego, CA
William Thomas Harless, M.D. is an internal medicine physician with a practice address in San Diego, California, and NPI 1366452823, issued on Aug 8, 2006. Check the license (California G27839, as entered in NPPES) on the Medical Board of California; the federal record below is the public data PlainDoctor holds for this provider.
- Name
- William Thomas Harless
- Credential
- M.D.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- G27839 CA
Self-reported in NPPES; status is on the state search - Practice location
- 300 Fir St, San Diego, CA 92101
- Phone
- (858) 499-2600
- Enumerated
- Aug 8, 2006
- Record last updated
- Jun 19, 2013 (not updated in 13 years: call before relying on the address or phone)
- Fax
- (619) 446-1569
- Medicaid ID
- 00G278390 CA
- Entity
- Type 1 · individual
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A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify William Thomas Harless in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license G27839Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
William Thomas Harless among 17,696 internal medicine physician records in California
William Thomas Harless, M.D. is one of 17,696 internal medicine physician records with a practice address in California. 79% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does not. Its NPI, issued in 2006, is newer than 5% of them.
- NPI issued2006 · 5% of these records are older, 56% newer
- In a Medicare fileNo · 79% of these records are
- In the CMS Doctors and Clinicians fileNo · 63% of these records are
- Record last updated2013 · 61% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207R00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
961 internal medicine physician records list a practice address in San Diego
They are 961 of the 52,937 NPPES records with a practice address in San Diego, and 17,696 internal medicine physician records in California. No Medicare prescribing, quality score, industry payment or hospital affiliation is published for this NPI.
All 17,696 in California → Every provider in San Diego → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Alicia Benjamin, M.D.San Diego, CA 921011790793040
- John Chau, M.D.San Diego, CA 921011740375070
- Michael Duffy, DOSan Diego, CA 921011851399802
- Brij Gupta, M.D.San Diego, CA 921011174532543
- Paul Hazelbaker, DOSan Diego, CA 921011831106103
- Mark Jabro, M.D.San Diego, CA 921011326058330
- Wayne Kurisu, M.D.San Diego, CA 921011881606309
- James Morgan, M.D.San Diego, CA 921011376553446
Common questions
What is William Thomas Harless, M.D.'s NPI number?
William Thomas Harless, M.D.'s National Provider Identifier (NPI) is 1366452823, issued on Aug 8, 2006. An NPI identifies a provider in billing; it is not a license.
Where is William Thomas Harless, M.D. located?
The NPPES record lists a practice address at 300 Fir St, San Diego, CA, 92101. Phone: (858) 499-2600. Providers update this record themselves, so call before visiting.
How can I verify William Thomas Harless, M.D.'s license?
NPPES lists California license number G27839, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.