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Crypto Law/Level IV · Holders' traps/4.3 When the state comes/Lesson 4

Crossing borders with crypto

What customs declaration rules do and do not cover, how border officers may search phones and hardware wallets, and why moving country can change your account and tax position.

Education, not legal, tax or investment advice. Crypto law differs between countries and states and changes often. Check the current rules where you live with a qualified lawyer or tax adviser before you act.

The lean path

The cheapest, lowest-tax, simplest and most private route the law allows, best first. Each step names the rule it rests on and the condition that keeps it lawful.

  1. Under current US rules crypto is not a ‘monetary instrument’ (31 C.F.R. §1010.100(dd)), so a hardware wallet needs no FinCEN Form 105; cash over $10,000 does, and definitions should be rechecked before each trip.
  2. Free opsec: leave the seed backup at home, travel with minimal wallet apps and balances, and never carry a photographed phrase; CBP searches only data on the device, and lying to officers is a separate crime (18 U.S.C. §1001).
  3. Zero-tax residency routes exist: Germany exempts private crypto sales held over one year (§23 EStG) and Portugal exempts non-professional holdings over 365 days (CIRS Article 10); US citizens are still taxed on worldwide gains.
  4. Renouncing US citizenship can trigger the §877A exit tax for covered expatriates, and US persons abroad keep FBAR and Form 8938 duties when thresholds are met; check the new country’s exit-tax rules too.

Materials31 CFR §1010.100(dd), the US definition of ‘monetary instruments’ for border reportingUS Customs and Border Protection’s page ‘Border Search of Electronic Devices’Regulation (EU) 2018/1672 on controls of cash entering or leaving the UnionA list of every device you travel with that holds a wallet app, keys or a seed backup

Wonder

  1. Do I have to declare crypto at the border the way I declare large amounts of cash?
  2. Can border officers make me unlock my phone or hardware wallet?
  3. What happens to my exchange account and my taxes if I move to another country?

Explore

  1. Crypto never physically crosses a border; the blockchain is everywhere at once. What crosses are the means of control: a phone with a wallet app, a hardware wallet, a written seed phrase, or the phrase in your memory. Border law reaches crypto through three doors: declaration rules for money carried across the border, the power of officers to search what you carry, and the tax and account consequences of changing where you live. Each works differently, and each differs between countries, so this lesson uses the United States and the European Union as examples.
  2. In the United States, 31 U.S.C. §5316 requires a report when a person carries monetary instruments of more than $10,000 at one time into or out of the country, using FinCEN Form 105. The regulation defining ‘monetary instruments’, 31 CFR §1010.100(dd), lists currency, traveler’s checks, certain negotiable instruments such as bearer checks and money orders, and bearer securities. Crypto is not on that list, so under the current definition a hardware wallet is not a Form 105 item, while cash from selling coins is. Definitions can be amended, so check the current form instructions before each trip rather than relying on memory.
  3. The European Union’s cash-control law, Regulation (EU) 2018/1672, requires travellers entering or leaving the Union with cash of EUR 10,000 or more to declare it. It defines ‘cash’ as currency, bearer-negotiable instruments, commodities used as highly liquid stores of value such as gold, and certain prepaid cards. Crypto-assets are not among the four categories, though the Regulation lets the Commission add items to the commodity and prepaid-card lists. Other countries set their own thresholds and definitions, and some treat crypto differently, so the destination’s customs website is the place to check, not a forum post.
  4. Searching is a separate power. US Customs and Border Protection distinguishes a ‘basic’ search, an officer looking through a device by hand, from an ‘advanced’ search, which connects equipment to copy or analyse the contents. Under CBP policy, an advanced search requires reasonable suspicion of a violation or a national security concern and approval from a senior manager. CBP says it examines only information resident on the device, disables network connections first, and may not use the device to reach data stored solely in the cloud. A device that cannot be inspected because of a passcode or encryption may be detained.
  5. Courts have not settled how far these searches may go. The US Supreme Court has not ruled on warrantless border searches of phones and similar devices, and federal appeals courts disagree: in 2018 the Fourth Circuit, in United States v. Kolsuz, required individualized suspicion for a forensic search, while the Eleventh Circuit, in United States v. Touset, held that no suspicion is needed. For a crypto holder the risk is exposure: a wallet app shows balances and addresses, and a photographed or written seed phrase gives total control of the funds to anyone who copies it (lesson 4.1.5).
  6. Moving country raises account and tax questions. Exchange accounts are licensed and verified by country of residence, so a move can trigger new verification or a restriction (lesson 4.3.1). The United States taxes its citizens on worldwide income wherever they live, and US persons with foreign accounts may face FBAR and FATCA reporting (lesson 2.3.6); most other countries tax by residence, so arriving can create new duties. A practical check before travelling: list each device that holds wallet software or keys, note what an officer could see on it, and confirm the declaration rules of every country you will enter or leave.

Key facts

  • 31 U.S.C. §5316 requires a report when a person carries monetary instruments of more than $10,000 at one time into or out of the United States.
  • The US definition of monetary instruments in 31 CFR §1010.100(dd) lists currency, traveler’s checks, certain negotiable instruments and bearer securities, and does not list crypto.
  • Regulation (EU) 2018/1672 requires a declaration of cash of EUR 10,000 or more carried into or out of the EU, defining cash in four categories that do not include crypto-assets.
  • Under CBP policy, an advanced search of an electronic device requires reasonable suspicion or a national security concern and senior manager approval.
  • CBP states that border device searches cover only information resident on the device and not data stored solely remotely.
  • In 2018 the Fourth Circuit (Kolsuz) required individualized suspicion for forensic border searches of devices, while the Eleventh Circuit (Touset) did not.

Exercise nine, six, three, one

9CollectList up to 9 things you might carry on a trip that could reveal or control crypto, such as a phone wallet, a hardware wallet, a seed backup, an exchange app, or a laptop.
6ClusterSort them into 6 categories: devices that hold keys, devices that only show balances, paper or metal backups, exchange apps, documents about holdings, and items with nothing crypto-related.
3DistillReduce the 6 categories to 3 groups: items that give control of funds, items that only reveal information, and items that carry no crypto risk.
1CrystallizeWrite 1 sentence describing what an officer conducting a basic search of your phone today would learn about your crypto.

Fact check

Dates, figures and claims checked against the published sources listed below.

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