Can we invoice Norwegian clients from our Portuguese Lda without registering in Norway?

Sometimes — genuinely remote B2B services are often reverse-charged to your Norwegian customer, meaning no Norwegian registration. But the exception is narrow: any physical presence, on-site work, B2C sales or goods delivery pulls you into registration territory, and crossing NOK 50,000 makes it mandatory. The usual story is a company that was fine for one invoice and non-compliant by the third. Check your concrete pattern before the first invoice.