What is William Fonseca's NPI number?

William Fonseca's National Provider Identifier (NPI) is 1639043169, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.

What is William Fonseca's specialty?

William Fonseca is listed in the NPPES registry with a primary specialty of Behavior Technician (Behavioral Health & Social Service Providers).

Where is William Fonseca located?

William Fonseca's practice location on file with NPPES is 1887 Mount Goethe Way, Antioch, CA 94531-9077.

What is William Fonseca's phone number?

The practice phone number listed in the NPPES registry for William Fonseca is (925) 690-7911.

Is William Fonseca's NPI active?

Yes — William Fonseca's NPI (1639043169) is active in the NPPES registry as of the last update on 2025-09-29.

IndividualActive

William Fonseca

NPI 1639043169 · Behavior Technician · Antioch, CA

William Fonseca is a Behavior Technician provider in Antioch, CA (NPI 1639043169).

Provider details

NPI number: 1639043169
Entity type: Individual
Primary specialty: Behavior TechnicianBehavioral Health & Social Service Providers
Sex: Male
Sole proprietor: No

Specialties & taxonomies

Behavior TechnicianPrimary106S00000X
Behavioral Health & Social Service Providers

Profile Score

Basic profile(47/100 index)

A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.

Registry tenure38% of score
Under 1 yr in registry
Profile completeness38% of score
83% of core fields populated
Practice footprint23% of score
1 documented practice location

Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.

Practice location

1887 Mount Goethe Way

Antioch, CA 94531-9077

Phone: (925) 690-7911

Street-level locationGet directions

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Mailing address