How to Become an ISA Certified Arborist
Short answer: build three years of full-time arboriculture experience (or one to two years plus a qualifying degree or training program), apply to ISA with proof, pay the exam fee, pass the 200-question exam with 76% or better, then renew every three years with 30 continuing education units. ISA's fees total $335 for members or $419 for non-members.
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Get the required experience
You need at least three years of full-time practical experience in arboriculture, or a shorter period combined with a qualifying degree or assessed training program. One year of full-time work counts as about 1,795 hours.
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Apply to ISA
Submit the Certified Arborist application on ISA's credentialing site with proof of experience (employer reference letters, or three references such as invoices or contracts if you are self-employed) and pay the $40 (ISA member) or $50 application fee. ISA reviews applications within five US business days.
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Enroll and schedule the exam
Once approved, pay the $295 (member) or $369 exam enrollment fee and choose a computer-based exam at a Pearson VUE test center or a paper exam with a local ISA Certification Partner. Computer-based candidates get a 120-day window to sit the exam.
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Pass the exam
The exam has 200 multiple-choice questions across ten domains and a 210-minute time limit. The passing score is 76%. Computer-based candidates see their result as soon as they finish.
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Keep your certification
Certification lasts three years. To renew, earn at least 30 continuing education units in the exam domains and pay the $220 recertification fee, or pass the exam again.
Eligibility requirements in detail
ISA accepts any one of these combinations:
- Three years of full-time practical experience in arboriculture
- Two-year associate degree with at least two arboriculture-related courses, plus two years of full-time experience
- Four-year bachelor's degree with at least four arboriculture-related courses, plus one year of full-time experience
- 900 hours of assessed training (at least 90 hours directly related to arboriculture), plus two years of full-time experience
- 1,800 hours of assessed training (at least 180 hours directly related to arboriculture), plus one year of full-time experience
- Approved registered or recognized apprenticeship programs may be accepted as equivalent
Degree courses and training hours must be directly related to arboriculture, and you send transcripts showing course titles and credit hours or training hours with your application. Multiple degrees cannot be added together to count as a longer program, but assessment-based certificate programs can be combined to reach the required hours.
What it costs
| Fee | ISA member or credential holder | Everyone else |
|---|---|---|
| Application | $40 | $50 |
| Exam enrollment | $295 | $369 |
| Total to sit the exam | $335 | $419 |
| Retake, if needed | $120 | $120 |
| Recertification every 3 years (CEU route) | $220 | $220 |
US dollars, from the ISA Program Guide (checked October 19, 2026). ISA does not refund exam enrollment fees.
Preparing for the exam
The exam covers ten domains, from tree biology and soils to pruning, tree risk and safe work practices. Most people study for several weeks: read ISA's study guide, practice each domain, and finish with timed mock exams. See our free study guide for an 8-week plan, the exam guide for format and rules, and the free practice questions to see where you stand.
Common questions
Can I become an ISA Certified Arborist without experience?
No. Every eligibility path includes practical, full-time arboriculture experience: three years on its own, or one to two years combined with a qualifying degree or assessed training program. Supervised volunteer work can count if you can document the duties and hours.
How much does it cost to become an ISA Certified Arborist?
ISA's fees add up to $335 for ISA members and credential holders ($40 application plus $295 enrollment) or $419 for everyone else ($50 plus $369), before study materials. A retake costs $120. Source: ISA Program Guide, checked October 19, 2026.
Is ISA certification the same as a license?
No. ISA's Program Guide states that its certifications are not a license, registration or authorization to practice or do business. Some states and cities have their own licensing rules for tree work, so check with your state and local government as well.
What kind of work counts toward the experience requirement?
Practical work that uses arboricultural knowledge, such as pruning, fertilization, planting and establishment, diagnosing and treating tree problems, cabling and bracing, and climbing. It can come from tree care companies, nurseries, landscape firms, municipalities, state forestry agencies, utilities, consultancies and similar employers.