Travel to Engage in Illicit Sexual Conduct Defense: 18 U.S.C. § 2423

By Elizabeth Franklin-Best, Esq., and Christopher Zoukis, JD, MBA

The federal travel statute reaches conduct across state and national borders, and it contains one provision — the transportation of a minor — that carries a ten-year mandatory minimum. If you are under investigation or charged under 18 U.S.C. § 2423, you need an 18 USC 2423 lawyer who reads the statute subsection by subsection, because each provision carries different elements and sharply different exposure — and Congress rewrote much of the section as recently as December 2023. At Elizabeth Franklin-Best, P.C., we defend clients against federal travel-offense allegations nationwide; this guide is part of our federal sex offense defense resource.

This guide explains, in clinical and factual terms, the federal travel statute — 18 U.S.C. § 2423 — its subsections, elements, penalties, and defenses. Our subject is the law and the defense of the accused.

Statutory precision sits at the center of our defense work, and few statutes reward it like § 2423. Elizabeth Franklin-Best, who leads the firm, is recognized as a 2026 “Best Lawyer” in Appellate Practice by Best Lawyers in America, and Chambers USA ranks her in 2026 for Litigation: White-Collar Crime & Government Investigations. Over the course of her career she has appeared in more than 330 federal proceedings — over 100 of them appeals — in all twelve federal circuits and at the United States Supreme Court, the breadth a subsection-driven statute like § 2423 rewards. We approach every travel-offense case by identifying the precise subsection charged, mapping its elements, and testing the government’s proof of intent. If you are facing a § 2423 investigation or charge, we invite you to book a paid, one-hour initial consultation with our team.

Travel Offenses: Quick Answer

Question	Answer
What is 18 U.S.C. § 2423?	The federal travel statute — it criminalizes transporting a minor, traveling with intent to engage in illicit sexual conduct, and engaging in such conduct in foreign places.
What must the government prove?	The elements of the specific subsection charged — which, for the travel provisions, generally include the required purpose or intent.
What penalties can apply?	Transportation of a minor under § 2423(a) carries a ten-year mandatory minimum, up to life; the travel provisions carry up to 30 years.
Are the subsections the same?	No. Section 2423 contains several distinct offenses with different elements and very different exposure.
Where does a defense start?	With a paid, one-hour initial consultation — we identify the subsection charged, the intent standard that governs your dates of alleged conduct, and the immediate next steps.

Key Takeaways

• 18 U.S.C. § 2423 is the federal travel statute, and it contains several distinct offenses.
• Section 2423(a) — transportation of a minor — carries a ten-year mandatory minimum and a maximum of life.
• Section 2423(b) — travel with intent to engage in illicit sexual conduct — carries up to 30 years.
• Section 2423(c) — engaging in illicit sexual conduct in foreign places — carries up to 30 years and does not require proof of intent at the time of travel.
• The statute also reaches arranging or facilitating travel, and attempts and conspiracies.
• The travel provisions generally turn on the defendant’s purpose or intent — a central, contestable element.
• Many § 2423(b) cases arise from undercover sting operations, raising entrapment and intent defenses.
• A conviction triggers sex offender registration under SORNA and extensive collateral consequences.

What the Travel Statute Covers

Section 2423 of Title 18 is the federal “travel” statute, codified in chapter 117 — the modern descendant of the Mann Act of 1910 — alongside the general transportation offense in § 2421. It is not a single offense — it is a cluster of related offenses, all built on the movement of a person across state or national lines, and they differ significantly in their elements and their penalties. Identifying precisely which subsection the government has charged is the first step in any § 2423 defense.

• Section 2423(a) — Transportation of a minor. Knowingly transporting an individual under 18 in interstate or foreign commerce with the intent that the individual engage in prostitution or any criminal sexual activity. This is the most severely punished subsection, carrying a ten-year mandatory minimum and a maximum of life.
• Section 2423(b) — Travel with intent. Traveling in interstate commerce, into the United States, or — for a U.S. citizen or permanent resident — in foreign commerce, with intent to engage in any illicit sexual conduct. Congress substituted this “with intent” language in December 2023 for the earlier “motivating purpose” phrasing. It carries up to 30 years.
• Section 2423(c) — Engaging in illicit sexual conduct in foreign places. A U.S. citizen or permanent resident who travels in foreign commerce — or resides, temporarily or permanently, in a foreign country — and engages in illicit sexual conduct. It carries up to 30 years.
• Section 2423(d) — Illicit sexual conduct in connection with certain organizations. Added in December 2023: a citizen or permanent resident who serves as an officer, director, employee, or agent of an organization affecting interstate or foreign commerce, uses the mails or means of commerce through that affiliation, and commits an act in furtherance of illicit sexual conduct through it. It carries up to 30 years.
• Section 2423(e) — Ancillary offenses. For commercial advantage or private financial gain, arranging, inducing, procuring, or facilitating a person’s travel knowing that the person is traveling with intent to engage in illicit sexual conduct — the “sex tourism” facilitation provision, re-lettered from (d) in 2023. It carries up to 30 years.
• Section 2423(f) — Attempt and conspiracy. Attempts and conspiracies are punishable in the same manner as a completed violation of the underlying subsection.

“Illicit sexual conduct” is a defined term in the statute. The differences among these subsections are not technicalities — they determine the elements the government must prove and whether a mandatory minimum applies.

The Intent and Purpose Elements

For the transportation and travel provisions, the defendant’s intent or purpose is usually the central, contested element.

Under § 2423(a), the government must prove the defendant transported a minor with the intent that the minor engage in prostitution or criminal sexual activity. Under § 2423(b), as rewritten in December 2023, the government must prove the defendant traveled with intent to engage in illicit sexual conduct — and a new rule of construction, § 2423(h), defines that intent as any intention to engage in the prohibited conduct existing at the time of the transportation or travel. Where the alleged intention was never formed, was formed only after the travel ended, or was abandoned before travel, the element remains contestable.

The 2023 language closes out a doctrinal argument that ran for eighty years. In Mortensen v. United States, 322 U.S. 369 (1944), the Supreme Court read the Mann Act to require that the illicit conduct be the dominant motive of the interstate journey — a trip taken for an innocent purpose did not become criminal merely because misconduct followed it. The circuits later softened that rule. The Ninth Circuit, sitting en banc in United States v. Flucas, 22 F.4th 1149 (9th Cir. 2022), upheld instructions requiring only that criminal sexual activity be “a dominant, significant, or motivating purpose” of the transportation — more than merely incidental, but not necessarily the sole or most important reason for the trip. Congress then amended § 2423(b) itself, in 2018 (“a motivating purpose”) and again in 2023 (“with intent”), expressly disclaiming any requirement that the unlawful aim be a primary, dominant, or motivating purpose. Which formulation governs depends on when the alleged conduct occurred — a point the defense should never concede silently.

Section 2423(c) is different and important to understand. Congress structured § 2423(c) so that the government does not have to prove the defendant intended, at the time of travel, to engage in illicit sexual conduct. For that subsection, the focus is on whether the defendant traveled in foreign commerce and engaged in illicit sexual conduct — the intent-at-the-time-of-travel requirement was deliberately removed. That distinction shapes the defense of a § 2423(c) case very differently from a § 2423(b) case.

Applied Insight: The subsection charged drives everything. A § 2423(b) travel case turns on proving intent existing at the time of travel; a § 2423(c) foreign-conduct case does not require intent at the time of travel at all. A defense that does not pin down — and litigate — exactly which subsection is in play, and what it requires, misses the case’s central fault lines.

What Changed in December 2023

Section 5102 of the December 2023 defense authorization act (Pub. L. No. 118-31) restructured § 2423 more extensively than any amendment in twenty years. Anyone reading older indictments, briefs, or case law against the current statute needs the map:

• The travel provision, § 2423(b), and the facilitation provision now require travel “with intent to engage” in illicit sexual conduct, replacing the 2018 “motivating purpose” wording.
• A wholly new offense, § 2423(d), reaches illicit sexual conduct committed through a person’s affiliation with an organization affecting interstate or foreign commerce — Congress cited abuse committed under cover of charitable, athletic, and missionary work.
• The former facilitation subsection (d) became (e); attempt and conspiracy moved to (f); the definition of “illicit sexual conduct” moved to (g); and the age-belief defense moved to (i).
• A new rule of construction, § 2423(h), provides that “intent” means any intention to engage in the prohibited conduct existing at the time of the transportation or travel.

For the defense, the re-lettering is more than housekeeping. Charging documents drafted from outdated templates, jury instructions built on pre-2023 purpose formulations, and precedent discussing subsections by their old letters all have to be checked against the statute as it existed on the dates alleged. Conduct is judged under the version of § 2423 in force when it occurred.

The Statutory Definition and the Age-Belief Defense

“Illicit sexual conduct” now lives in § 2423(g), and it has three prongs: a sexual act with a person under 18 that would violate chapter 109A had it occurred in the special maritime and territorial jurisdiction of the United States; a commercial sex act, as defined in § 1591, with a person under 18; and the production of child pornography as defined in § 2256(8) — a prong Congress added in 2015. Because the travel, foreign-conduct, organizations, and facilitation offenses all incorporate this definition, the prong the government selects determines what it must prove.

The statute also contains an affirmative defense, now codified at § 2423(i). In a prosecution based on the commercial-sex-act prong, it is a defense that the defendant reasonably believed the other person had reached 18 — but the defendant must establish that belief by clear and convincing evidence, a standard Congress raised from preponderance in 2015. The defense does not extend to the other prongs of the definition, which makes identifying the government’s theory early a practical necessity.

Travel Cases and Sting Operations

Many § 2423(b) prosecutions arise from undercover sting operations. They frequently overlap with online enticement cases: a target communicates online with someone he believes to be a minor — in fact an undercover officer — and then travels to a planned meeting, where an arrest is made. The travel is charged as a § 2423(b) offense; the communications are often charged as enticement under § 2422(b). Consistent with that posture, the Seventh Circuit in United States v. Fuchs, 118 F.4th 911 (7th Cir. 2024), observed that the crux of a § 2423(b) offense is travel with the purpose of engaging in sexual activity with a minor and that “[t]he actual age of the intended victim is not an element of the offense” — so a defendant’s belief that he was arranging to meet a minor can support conviction even where the “minor” was an undercover officer. That stands in deliberate contrast to § 2423(c), under which, as the same court noted, the victim’s age is an element because the offense requires actually engaging in illicit sexual conduct abroad.

Because these cases are built on sting operations, the same two defenses that are central to enticement cases apply here: entrapment — where the government induced an offense the defendant was not predisposed to commit — and intent — whether the government can prove the travel was undertaken for the unlawful purpose the statute requires. As in enticement cases, the complete record of the communications, in context and in sequence, is decisive. Who introduced the unlawful subject, who escalated it, and how the plan to travel developed are the facts on which a § 2423(b) case is defended.

Penalties for Travel Offenses

The penalties under § 2423 vary sharply by subsection. Transportation of a minor under § 2423(a) is the most severe, carrying a ten-year mandatory minimum and a maximum of life imprisonment. Travel with intent under § 2423(b) and engaging in illicit sexual conduct in foreign places under § 2423(c) each carry a maximum of up to 30 years. The organizations offense under § 2423(d) and the ancillary-offenses provision under § 2423(e) each carry up to 30 years, and § 2423(f) punishes attempts and conspiracies in the same manner as completed violations.

Beyond the sentence, a conviction triggers sex offender registration under SORNA, lengthy or lifetime supervised release, and extensive collateral consequences for employment, housing, residency, family matters, and immigration status.

In federal court, the advisory United States Sentencing Guidelines drive any sentence above a mandatory minimum. A sentencing defense can present the full mitigating circumstances of the individual. Because the exposure differs so dramatically between the mandatory-minimum § 2423(a) offense and the other subsections, the charging analysis and the defense to the most serious count are critical.

Defenses to Travel-Offense Charges

No two travel-offense cases are alike, and no lawyer can promise a result. But several defense themes recur, and matching them to the evidence is the core of building a strategy:

• No unlawful purpose. For § 2423(a) and (b), the government cannot prove the required intent or purpose — the travel or transportation had legitimate purposes.
• Entrapment. In a sting case, the government induced an offense the defendant was not predisposed to commit.
• The communications in context. The full record does not support the intent the government alleges.
• No belief a minor was involved. Where the offense depends on the involvement of a minor, the defendant did not believe a minor was involved.
• Subsection-specific defenses. Holding the government to the precise elements of the subsection charged — and the absence of a mandatory minimum where § 2423(a) does not apply.
• Identity. The government cannot prove the defendant, rather than another person, is responsible.
• Fourth Amendment and process challenges. The manner in which evidence and devices were obtained can be litigated.
• Sentencing advocacy. Rigorous sentencing work and full mitigation.

The right combination depends entirely on the facts and the subsection charged. Our role is to test the government’s proof element by element, develop the favorable record, and press every legitimate defense — during the investigation, in pretrial motions, at trial, and on appeal.

How Travel-Offense Investigations Begin

Travel-offense investigations arise from undercover sting operations, from online communications monitored or reported by platforms, from border and travel records, from international cooperation, and from referrals to federal task forces. A § 2423(b) case frequently culminates in an arrest at a planned meeting location.

What you do at the first contact with law enforcement is critical. You are not required to answer agents’ questions or to consent to a search of your devices. An unprepared interview can be deeply damaging, particularly on the intent element. Decline to be interviewed, preserve your rights and all communications records, and consult an experienced 18 USC 2423 lawyer before saying anything substantive.

Why Work With Elizabeth Franklin-Best, P.C.

Travel-offense cases reward defense lawyers who identify the precise subsection charged, who understand the different intent requirements of each, who know the entrapment defense, and who reconstruct the complete communications record in sting cases.

Elizabeth Franklin-Best — the author of Reversing Your Criminal Conviction — is admitted before the U.S. Supreme Court and every one of the twelve federal circuit courts of appeals, and she takes district-court matters nationwide through pro hac vice admission. Christopher Zoukis, the firm’s Managing Director, covers the sentencing-mitigation and Bureau of Prisons dimensions that loom large whenever a mandatory minimum is on the table. From the first agent contact through appeal, we handle travel-offense cases with the discretion they demand.

Outcome promises have no place in a § 2423 case, and you will not hear them from us. What you should expect instead: a subsection-by-subsection reading of the indictment, a frank evaluation of the intent evidence, and a defense plan built on the statute as Congress most recently wrote it. If a travel-offense investigation or charge is in front of you, the starting point is a paid, one-hour initial consultation.

Talk With a Travel-Offense Defense Lawyer

Depending on the subsection, a § 2423 case can mean a ten-year mandatory minimum or a thirty-year ceiling — and the intent element is usually being built, through interviews, devices, and travel records, well before any charge is filed. Bringing an 18 USC 2423 lawyer into that window preserves defenses that are difficult to recover later. Call our team to arrange a paid, one-hour initial consultation; our guides on federal sentencing and collateral consequences explain what rides on the result.