Business connection
Convention attendance is deductible if it benefits your trade or business. Section 274(h) imposes additional substantiation requirements for foreign conventions and caps cruise-ship conventions at $2,000 per year. Domestic conferences directly related to your industry, profession, or business operations are clearly deductible.
What you can deduct
Registration fees, travel to and from the venue (airfare, mileage, rental car), lodging, 50% of meals, business calls, and reasonable tips. Bringing a spouse: their costs are deductible only if they are an employee or partner of the business AND have a bona fide business reason to attend.
Side trips and extended stay
For a domestic conference, you can extend your stay for personal time without losing the airfare deduction (transportation is fully deductible if the trip is primarily business). Lodging and meals on the personal days are not deductible. For foreign conferences, allocation rules are stricter.
Cruise ship conventions
Cruise-ship conventions are deductible only if (a) the cruise is on a US-flag vessel, (b) all ports are in the US or its possessions, (c) the convention is directly related to your trade or business, and (d) you attach a written statement to your return. The deduction is capped at $2,000 per attendee per year.
Educational vs networking
Both qualify if the conference is business-related. Documenting the business connection helps — keep the conference agenda, your registration confirmation, your CEU certificate (if applicable), and notes from sessions you attended. Notes need not be detailed; their existence is the point.
Where this fits in the larger Schedule C picture
Schedule C has more than two dozen named expense lines plus an "Other expenses" catch-all. For most small businesses, four or five lines drive the bulk of the deduction total — vehicle, home office, depreciation, contract labor or wages, and supplies — and the remaining lines individually contribute small amounts that nevertheless add up. Treating each named line as a recurring decision rather than an afterthought, and revisiting the categories each January, often surfaces $2,000–$5,000 in additional legitimate deductions that a less disciplined process would have missed entirely.