In B2B Europe, a clean mobile caller ID gets answered most often, a geographic landline comes second, non-geographic VoIP ranges come last, and a masked number barely gets answered at all. The type of number matters less than its reputation and the slot you call in, but when everything else is equal, prospects pick up a mobile.

Here is why, the exceptions by sector and persona, and how to set up a number pool that stays clean.

What the caller ID tells the prospect before you speak

A prospect sees ten digits and decides in a second. The prefix carries a story.

• Mobile (06/07 in France). "A person is calling me." It could be a client, a candidate, a partner. The cost of missing it feels high, so people pick up.
• Geographic landline (01 to 05). "A company is calling me." Fine if it is a local company, less so if a Paris 01 calls Marseille, which reads as a call centre.
• Non-geographic (09, and the ranges reserved for telemarketing). "A platform is calling me." In our experience these pick up noticeably less among decision-makers, and in France some ranges are formally designated for prospecting calls, which tells the prospect exactly what is coming.
• Masked. "Someone is hiding." Decision-makers almost never answer, and many phones silence it by default.

The hierarchy is consistent across the European markets we see. What changes by country is the prefix, not the psychology.

Why a mobile wins by default

Three reasons, in order of weight.

It reads as personal. B2B decision-makers in France receive far more sales calls on landlines than on mobiles, because landlines are what data vendors sold for years. A mobile call still feels like it might be someone they know.

It reaches the person, not the desk. Our benchmark of 1,000,000 B2B cold calls in France gives an average connect rate of 11.3%. Much of the gap between 11% and 20% comes from whether you have the person's direct line at all. A switchboard number is a connect with a receptionist, not with your prospect.

It is filtered less. Corporate switchboards screen. Mobiles ring. The mobile's filters (unknown-caller silence, screening) exist, but they are set by the individual, and most people never change defaults.

The counterweight is cultural. Some senior profiles in finance, industry or the public sector consider a cold call on their mobile intrusive. That is where a geographic landline, and a good reason to call, do better.

Exceptions by sector and persona

Tech, SaaS, agencies, recruiting

Mobile first. These personas live on their phones and expect direct contact. Founders pick up more around 10am, marketing around 4pm in our data; combine mobile caller ID with the right slot.

Finance, insurance, industry

Mixed. A geographic landline reads as an established company and suits C-level contacts who guard their mobile. Keep a mobile for follow-ups once a first exchange has happened.

Regional businesses

Local geographic number. A 04 calling Lyon or a 05 calling Bordeaux signals "someone from here". A national mobile still works; a Paris landline does not.

HR and public sector

Landline during office hours. HR picks up more around 1pm in our benchmark, often from a desk phone.

In every case, the number type is a small lever against the big ones: slot, persona, list quality and number reputation.

Virtual numbers: what they are and what they are not

A virtual number is a normal number whose endpoint is a software account instead of a physical line. A virtual mobile looks like any mobile; a virtual geographic number looks like any landline. The prospect cannot tell. What matters is the prefix it carries and whether it is registered and authenticated to your company.

So the "virtual versus real" debate is a false one. The real questions are: is the prefix right for the persona, does it ring back to someone, and is it clean? In France, caller-ID authentication (mandatory on fixed lines since October 2024, with mobiles following) means a virtual number from a serious provider is attested like any other, and a number you do not hold cannot be displayed at all.

Never use a personal mobile for prospecting. It cannot be rotated, it cannot be retired when flagged, and it leaves the company with the rep.

Setting up a number pool that stays clean

1. Give each rep several numbers. A mobile as default, a geographic number for the sectors above. The dialer rotates them.
2. Cap volume per number. A number carrying a call-centre load gets flagged, whatever its prefix.
3. Test new numbers before use. Recycled numbers can arrive with a reputation.
4. Track connect rate per number weekly. A number a third below the team average is retired.
5. A/B test by type on one segment. Same list, same slots, same opener, mobile against landline for two weeks. Keep the winner for that segment. In our experience the gap is real but segment-specific.

Then put the effort where the data says it pays: 4pm beats 8am by 60% on connect rate in our benchmark (15.8% against 9.8%), and a trigger-based opener reaches a 7 to 10% meeting rate against 2 to 3% for a pitch-first one. No prefix delivers that.

How Sonik approaches caller ID choice

Sonik provisions European business numbers inside the platform, mobile and geographic, and assigns a pool per rep. The dialer rotates numbers, caps daily volume per number, and reports connect rate per caller ID so a team can see which type works on which segment instead of guessing.

Caller ID is one setting among the ones that matter more to us: parallel lines so reps get 5x more conversations, CRM signals so the call has a reason, and call prep so the opener is specific. We run the same setup internally against a target of 20 conversations per SDR per day. Details at sonik.ai/dialer.

Conclusion

Default to a clean, registered mobile caller ID, switch to a geographic landline for traditional sectors and regional targets, avoid non-geographic ranges and never mask. Then forget the prefix and work on slots, lists and openers. This week, run a two-week A/B on one segment, mobile against landline, same everything else, and let the connect rate decide.