May 8, 2026, 10:22 am | Read time: 3 minutes
Admittedly, the title of our news is a bit pointed. But looking at a recent report from Vodafone, most spam calls hit consumers midweek. The risk of falling victim to such a call and getting caught in a trap is particularly high on this day.
A year after the introduction of the protection system against phone fraud, Vodafone takes stock with a comprehensive review. Current data from the Spam-Warner shows how widespread phone fraud is, when perpetrators are particularly active, and why technical warning systems help but do not offer complete security.
Wednesday as the Focus of Fraud Attempts
In total, 64.5 million warning messages were sent to mobile phones over the past twelve months. Users receive the alert “Caution: Possible Fraud” when a number is classified as untrustworthy in a database.
According to the analysis of the Spam-Warner, the systems sound the alarm particularly often on Wednesdays—on average about 273,000 times a day. The weekend is much quieter: Saturdays see around 44,000 warnings, and Sundays only about 5,000. Apparently, fraudsters also adjust their activities to traditional working hours and take a break on weekends.
Other providers observe similar trends as well. For example, Telekom registers between 400,000 and 600,000 potential fraud attempts on weekdays, while the numbers drop significantly on weekends.
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Effectiveness of the Warning System and User Behavior
In addition to activity data, the analysis also shows how effective technical protective measures are against such spam calls. Only about 14 percent of calls with a displayed warning are answered at all. Without a warning—such as with suppressed numbers—the acceptance rate is about 60 percent.
Even if consumers answer a suspicious call, the conversations usually remain short. On average, they last about 40 seconds. By comparison, normal phone calls in the Vodafone network average a duration of 2 minutes and 40 seconds.
Overall, around 185,000 warning messages are issued daily, according to Vodafone. The highest recorded number was on May 27, 2025, with 660,000 alerts. Since December, the number of warnings has decreased by more than 20 percent, which Vodafone attributes in part to technical countermeasures.
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Origin of Calls and New Fraud Methods
The majority of suspicious calls originate from Germany, about 83 percent. Other common sources are the Netherlands, Austria, and the United Kingdom. Occasionally, numbers from countries like Cyprus or Lesotho appear.
Experts also warn of an increasing professionalization of the perpetrators. Criminals are increasingly using artificial intelligence and so-called deepfakes to mimic voices convincingly and gain trust. Older people are considered particularly at risk.
Despite technical protective mechanisms, it remains crucial to stay alert with unknown calls and carefully verify the identity of the caller. TECHBOOK lists the spam numbers that cause the most trouble each month and also reveals how users can block them on their smartphone, landline phone, or router.