Are extensions and renewals allowed for H-1B1 visas (for Singaporeans)?

Yes, but the two words describe different things. H-1B1 status, the specialty occupation category created by the U.S.-Singapore Free Trade Agreement, is granted one year at a time. Staying longer is routine and there is no fixed lifetime ceiling in the H-1B1 provisions, yet each additional year has to be applied for, and the requirements tighten as the years accumulate.

Extending the stay from inside the United States. The period of authorized admission is one year, and it may be extended only in one-year increments (INA 214(g)(8)(C)). The employer files the petition with USCIS before the Form I-94 expires (8 CFR 214.1(c)(1)). What that produces is a new I-94 period, not a new visa; the visa in the passport is unaffected.

Renewing the visa abroad. H-1B1 is not petition-based, so a replacement visa is applied for directly at a U.S. consular post rather than through USCIS. The visa itself is issued for up to 18 months for Singaporean nationals under the Department of State reciprocity schedule, which is a travel document period rather than a period of stay. Unlike H-1B, H-1B1 carries no dual intent protection: the presumption of immigrant intent in INA 214(b) applies, so each renewal calls for evidence that the stay remains temporary.

The attestation behind each year. Every period of H-1B1 employment must rest on a labor condition application certified by the Department of Labor under INA 212(t), filed no earlier than six months before the employment start date. A further rule applies to long stays: after every second extension, the next one cannot be granted unless the Department of Labor has certified that the employer filed an attestation specifically to support that extension (INA 214(g)(8)(C)).

Effect on the annual cap. The 5,400 Singapore and 1,400 Chile limits apply to initial approvals only, so an ordinary extension does not consume a new number. One narrow exception exists: the general 65,000 H-1B cap is reduced by one for each H-1B1 extension granted during a fiscal year to a worker who already holds five or more consecutive prior extensions (INA 214(g)(8)(D)).