In Austria, a cold B2B phone call is illegal. Not discouraged, not a grey area: prohibited without prior consent, with fines to €58,000 a violation. Drive an hour north and the same call is allowed in Germany, provided your offer plausibly fits the business you are ringing. Drive to the Netherlands and it is allowed.

Cold outreach advice is written as if there were one law. There isn't. The channel and the recipient's country decide together, and the answer changes for every pair.

We built this table for ourselves. We mail letters and then follow them up, so we needed to know, per prospect, which follow-up we were allowed to send. It covers the channels we researched on the date above. Where a rule is unsettled we say so instead of rounding it to a yes.

Almost nothing here turns on whether your outreach is polite. It turns on whether the recipient consented, whether consent can be presumed, and whether you can prove it. Those are three different tests, and most of the difference between countries is which one applies.

The letter

A letter is the only channel here with scarcity. An inbox holds two hundred unread messages and costs nothing to add to. A desk holds three things, and putting a fourth there costs a stamp, a sheet of paper, and the time to research the person it is addressed to. That asymmetry is the mechanism. A letter is not more persuasive than an email. It is harder to ignore before it has been read, and that second of attention is what you are buying.

The cost is also the constraint. Letters are slow, they cannot be tested at volume, and there is nothing to click. Ours carry a QR code, so a scan turns a piece of paper into a number. Use the letter as the opener that earns you a name, not as the sequence.

Post is governed differently from everything below. The rest of this page is about electronic communication, which is what we researched. For our own letters the basis is legitimate interest under GDPR Art. 6(1)(f), and because we did not get the address from the recipient, Art. 14 obliges us to tell them where it came from. Every letter points at a notice naming the controller, the source, the purpose, and how to object.

The LinkedIn message

LinkedIn is the cheapest way to stop being a piece of paper and start being a face. The identity is verified, being approached about work is expected there rather than resented, and the recipient can check who you are in one click. That is what people do after an unexpected letter turns up on their desk.

It is the legal outlier, because what binds you is mostly not statute. One-to-one outreach is broadly accepted and governed by LinkedIn's own terms rather than the §7 UWG case law that shapes calls and email. The data processing rests on GDPR Art. 6(1)(f). The verdict is the same in every country in this table, which is true of no other channel.

What gets accounts flagged is not the message, it is the automation. LinkedIn polices bulk connection and messaging tools, and it enforces the penalty itself. No court is involved.

The email

Email is the only channel that scales at no marginal cost and the only one where replying takes a keystroke. That makes it good follow-up and poor opening. An email from a stranger has no scarcity working for it. The same message that gets ignored cold gets answered four days after something physical landed with the same name on it.

This is where the law splits hardest. Germany and Austria treat B2B cold email as strictly consent-based under §7(2) Nr. 2 UWG. No presumption, and no warm-lead relief. People assume the warm-lead relief exists. It does not. Common practice leans on legitimate interest under Art. 6(1)(f) plus a clear opt-out and honest sender identification, which is a risk position, not a permission.

France is far more permissive: B2B email to a corporate address is fine without opt-in, if you identify yourself and offer an opt-out. Spain and Italy are formally stricter, though legitimate interest plus opt-out is the accepted practice. The United States is the simplest jurisdiction on this page. CAN-SPAM is opt-out based, so no consent is required. Identify yourself, do not use a deceptive subject line, honour every opt-out.

The phone call

The call is the only synchronous channel, and that is its whole argument. Ninety seconds on the phone tells you what three weeks of email never will, including the answer most sequences are built to avoid hearing. If a prospect is not a fit, a call is the fastest way to find out and stop spending on them.

Timing carries most of it. We place the call at day 16, after the letter has landed and the lighter follow-ups have run, because a call from someone whose letter is still on the desk is a different conversation from a call out of nowhere. The direct-mail convention is tighter still, at 24 to 72 hours after the piece arrives. The principle under both: the call should reference something the recipient can see.

It is also the most regulated channel we use, and the one where countries diverge most. Austria prohibits B2B cold calls without prior consent. An existing business relationship is the only exception, and fines run to €58,000 a violation. That is strict enough that our own system does not draft the step at all for an Austrian prospect, rather than leave the decision to a tired founder at 6pm.

Germany permits the call only under "presumed consent": your offer must plausibly match the recipient's business (§7(2) UWG). That is a real test, judged on the facts, not a formality. Switzerland allows the call unless the number carries a star entry in the directory (Art. 3(1)(u) UWG-CH). Unlisted numbers are off limits too, and fines reach CHF 20,000. France and Spain both run mandatory opt-out registers you must scrub against, and France moves consumer calls to a consent basis during 2026.

The United States and Canada are permissive for the specific thing we do: manual B2B calls to business numbers are exempt from the FTC's Telemarketing Sales Rule do-not-call provisions. The caveats matter. The TCPA has no B2B exemption for autodialed or prerecorded calls to mobile numbers, and Florida, Oklahoma, Washington and Maryland run mini-TCPAs with no B2B carve-out. Dial manually and the exemption holds. Automate and it does not.

The table

Where a cell is conditional, the condition is the rule. Read the note, not the verdict.

Recipient country	Phone call	Email	LinkedIn
Germany	Conditional. Presumed consent only: the offer must plausibly match their business (§7(2) UWG).	Conditional. Strictly consent-based even B2B (§7(2) Nr. 2 UWG). No presumption, no warm-lead relief. Practice basis: Art. 6(1)(f) plus opt-out plus sender identification.	Permitted. Governed mainly by LinkedIn's terms rather than §7 UWG case law. Bulk automation is what gets flagged.
Austria	Prohibited. No B2B exception without prior consent. Existing relationship only. Fines to €58,000 per violation.	Conditional. As Germany.	Permitted. Same verdict.
Switzerland	Conditional. Allowed unless the number carries a star entry (Art. 3(1)(u) UWG-CH). Unlisted numbers off limits. Fines to CHF 20,000.	Permitted. Legitimate interest plus opt-out. FMG also bans unsolicited mass advertising.	Permitted. Same verdict.
France and Spain	Conditional. Permitted, but both run mandatory opt-out registers to scrub against. France moves consumer calls to consent during 2026.	Permitted. France: B2B email to corporate addresses without opt-in, if you identify yourself and offer an opt-out. Spain is formally stricter; legitimate interest plus opt-out is accepted practice.	Permitted. Same verdict.
Rest of EU	Permitted. Generally allowed B2B. Netherlands: identify yourself and honour objections permanently.	Permitted. Legitimate interest (Art. 6(1)(f)) plus opt-out, broadly accepted for relevant B2B contacts.	Permitted. Same verdict.
US and Canada	Permitted. Manual B2B calls to business numbers are exempt from the FTC TSR do-not-call rules. No TCPA B2B exemption for autodialed or prerecorded calls to mobiles; FL, OK, WA and MD run mini-TCPAs without B2B carve-outs.	Permitted. CAN-SPAM is opt-out based. No consent required; identify yourself, no deceptive subject, honour every opt-out.	Permitted. No GDPR; the terms of service still apply.

Two channels we cut

Fax

We looked at it seriously. A surprising number of DACH SMBs still publish a fax number, and a document that emerges from a machine in an office has some of a letter's scarcity. It is memorable in a way that is hard to buy.

It is prohibited. Germany and Austria require prior express consent for advertising by fax, B2B and B2C alike, under §7(2) UWG. That is a stricter standard than the phone, and the burden of proof sits on the advertiser. The United States bans unsolicited advertising faxes under the Junk Fax Prevention Act. There is no version of this that works.

The two-cent bank transfer

We considered it, and the idea has real appeal. Send €0.02 to a published company IBAN with your pitch in the reference line, and you reach the one inbox every business reads: the bank statement. Nobody filters it. Nobody has built a spam rule for it.

A German court has already ruled on it. In LG Wiesbaden, 1 June 2021, 11 O 47/21, one-cent transfers carrying advertising in the reference line were held to be actionable spam under §7(2) Nr. 3 UWG, plus a hidden-commercial-purpose violation under §5a. The intuition that the recipient is receiving money rather than losing something is explicitly no defence. Austria would be expected to follow. Elsewhere it is untested, which is not the same as permitted.

It also fails on its own terms. We checked whether the channel could exist outside the German-speaking market at all. Of 21 SMB websites sampled outside DACH, zero published an IBAN. A channel that is unlawful where the addresses exist, and has no addresses where it might be lawful, is not a channel.

Sources

Phone: DACH and EU

Phone: United States

Email

Fax

IHK Köln, Werbung per Telefon, Fax und E-Mail. The IHKs uniformly state express consent for fax, B2B included.

The two-cent transfer

Cadence timing

Apollo, Ideal cadence for a multi-channel outbound sequence
Flagship Press, With B2B direct mail, follow-up timing is everything. Call 24 to 72 hours after the piece lands.

This is a working reference compiled for our own outreach, not legal advice, and it is accurate to the date at the top rather than to today. Rules move: France changes during 2026. And a position that is common practice is not a position that is settled. Where money or a regulator is involved, ask a lawyer in the recipient's jurisdiction. Coverage is the channels and countries named above. Anything outside them is not researched here, which is not the same as permitted.

What you may legally send, and where