How to Onboard a New Employee Properly: What to Do in the First 90 Days

You spent weeks finding the right person. You made the offer, they accepted, and now they are about to walk through your door. What happens next will determine whether they are still with you a year from now.

Most business owners put enormous effort into recruitment, then hand a new starter a laptop and hope for the best. That is not onboarding. That is guesswork. And according to Glassdoor, companies with a structured employee onboarding process improve new hire retention by 82%. Yet only 12% of employees say their organisation does it well.

The gap between those two numbers is where people leave. Not because the job was wrong for them, but because nobody set them up properly.

This guide covers your legal obligations, the practical steps that make a new starter feel genuinely set up for success, and what to focus on at each stage across the first 90 days.

Why the First 90 Days Are Make or Break

The first three months in a new job are when people decide whether they made the right choice. They are asking themselves whether the role matches what they were promised, whether the team feels like a good fit, and whether the business is somewhere they can see themselves growing.

If you leave them to figure things out alone, give them no structure, or fail to follow through on what was discussed at the interview, you will lose them. Research from InsightGlobal found that 22% of new hires leave within the first 90 days. Replacing a member of staff can cost anywhere between six and nine months of their salary once you account for recruitment costs, lost productivity, and management time.

A well designed employee onboarding process does not just make new starters feel welcome. It communicates your expectations clearly, gets them up to speed faster, and sets the working relationship on the right footing from the start.

Your Legal Obligations Before Day One

Before you think about the welcome email or the team introduction, there are legal requirements you must meet. Getting these right is the foundation on which everything else is built.

Written Statement of Employment Particulars

Under the Employment Rights Act 1996, as amended, you are required to give every employee a written statement of their main employment terms from day one. This is not optional, and it is not something you can delay. Prior to April 2020 employers had two months to provide this. That is no longer the case.

The statement must cover pay, hours, holiday entitlement, notice periods, job title, place of work, and several other specified particulars. A properly drafted employment contract covers all of this and gives you a legally sound foundation for the entire employment relationship.

If you are still using a contract downloaded from the internet, or a template that has not been reviewed in years, you may already be in a weakened legal position. A contract that does not reflect your business or meet current legal requirements leaves you exposed the moment anything goes wrong. It also makes it much harder to manage probation fairly, which we will come to shortly.

Right to Work Checks

You are legally required to check that every new employee has the right to work in the UK before they start. Failure to carry out a compliant check can result in a civil penalty of up to 60,000 pounds per illegal worker. The UK government's guidance on right to work checks sets out exactly which documents are acceptable and how the process works. Keep a copy of what you have checked on file.

Workplace Policies and Procedures

Your core workplace policies and procedures should be in place and shared with new starters from the outset. At a minimum, that means your disciplinary and grievance procedure, your sickness absence policy, your equal opportunities policy, and your health and safety arrangements.

If you do not have documented policies, you are highly vulnerable at employment tribunal. Policies are not bureaucracy. They are your first line of legal defence, and they are what give you the authority to manage people consistently and fairly.

Employee Handbook

A tailored employee handbook brings all of your policies, procedures, and expectations together in one place. When you share this with a new starter during onboarding, they cannot later claim they did not know what was expected of them. It also communicates your culture, values, and way of working in a way that a list of policies on their own simply cannot.

Probationary Period

Every new starter should have a clearly defined probationary period set out in their employment contract. This gives both of you a structured review point and, critically, it gives you the most straightforward legal route to part ways if things are not working out. If the probationary terms are vague, undocumented, or simply not there, you lose that protection entirely. Make sure your contract is clear on the duration, the notice period during probation, and how performance will be reviewed.

The 90 Day Employee Onboarding Process: Stage by Stage

A strong onboarding process has three distinct phases. Here is how each one works in practice.

Before They Start: Pre-Boarding

Onboarding does not begin on day one. It begins the moment someone accepts your offer. The period between acceptance and start date is your opportunity to get ahead and make sure your new starter arrives feeling prepared and valued rather than anxious and uncertain.

• Send a warm welcome message within 48 hours of their acceptance
• Confirm their start date and time, location, who to ask for, and any practical details like parking or building access
• Let them know what their first day will look like so they arrive with confidence
• Prepare their workspace, equipment, and any system logins they will need
• Brief the existing team so nobody is caught off guard
• Ensure the employment contract and right to work documents are finalised before day one

Week One: First Impressions Count

The first week sets the tone for everything that follows. Your goal is to make your new starter feel genuinely welcome, give them the context they need to understand your business, and help them start building the working relationships that will matter most to their success.

• Meet them personally on arrival, even briefly
• Introduce them to the team properly, not just a wave across the office
• Walk them through the business: what you do, why you do it, and how their role contributes
• Cover the practical day-to-day essentials: systems, processes, and who to go to for what
• Share and review the employee handbook and key policies together so there are no surprises
• Explain the probationary period clearly: what it involves, how it works, and what you will be reviewing
• Set a check-in for the end of the first week to see how they are settling in

The First 30 Days: Building Competence and Confidence

The first month is about getting your new starter up to speed and making sure they have what they need to perform well. It is also the point at which early warning signs tend to appear if things are not going to work out. Pay attention.

• Assign a buddy or mentor if your team size makes that practical
• Set clear, realistic objectives for the first 30 days so they know what success looks like
• Hold a formal one-to-one at the end of week two and again at week four
• Address any concerns or gaps in knowledge early, before they become habits
• Keep communication open and check in informally as well as formally
• Document any performance concerns in writing, even at this early stage

Days 31 to 60: Getting Into the Role

By the second month, most new starters should be finding their feet. The focus now shifts from learning the basics to building real confidence in the role and beginning to contribute meaningfully.

• Review progress against the initial 30 day objectives honestly and openly
• Set new objectives for the next 30 days, building on what has been achieved
• Identify any training needs and make a plan to address them
• Involve them more actively in team decisions and conversations
• Gather their feedback on how the onboarding process has felt from their side

Days 61 to 90: Confirming the Relationship

The final phase of the employee onboarding process is about confirmation. By the end of 90 days, you should have a clear picture of whether this person is the right fit for your business, and they should feel settled, capable, and invested in where they are heading.

• Conduct a formal 90 day review and document it
• Recognise what they have achieved and what has gone well
• Be honest about any development areas and agree on a plan
• Talk about longer term goals, so they feel a real future with you
• Confirm the ongoing reporting structure and any changes to objectives going forward
• Make a clear decision about whether to confirm their employment or, if necessary, how to handle the end of probation

If an employee is not working out, the probationary period is your most important opportunity to act. You need documented concerns, a fair process, and the right contractual terms in place. If things reach the point where disciplinary or performance management is required after probation, having kept records from the very first week will make an enormous difference to your position.

It is also worth being aware that if an employee goes off sick during or shortly after onboarding, you will need to manage that carefully. Our guidance on long-term sickness management explains how to handle absence in a way that is fair, legally compliant, and in your business's best interests.

Your 90 Day Onboarding Checklist

Use this as a practical reference when bringing any new starter into your business.

What Happens When Onboarding Goes Wrong

Poor onboarding costs businesses far more than most owners realise. When people leave in the first few months, they rarely tell you it was down to the onboarding experience. They cite the role, a better offer, or a change of direction. But the underlying truth is usually simpler: they never felt properly set up, and they stopped believing the business was worth staying for.

The knock-on effects go beyond the cost of replacing someone. If the departing employee was poorly inducted, there is a good chance their successor will be too. That cycle is expensive and entirely avoidable.

There are also scenarios that can emerge during or just after onboarding that carry real legal risk. If a new starter raises a grievance, is involved in a redundancy situation, or is affected by a TUPE transfer shortly after joining, having the right documentation and processes from day one will protect you significantly. Our teams cover all of these areas: redundancy and restructuring, TUPE, and disciplinary and performance management.

The Link Between Great Onboarding and Long-Term Retention

When you invest time in getting the employee onboarding process right, you get:

• Faster time to full productivity, because new starters have the information and support they need from day one
• Lower turnover, because people who feel valued and well set up are far more likely to stay
• Fewer early conduct and performance issues, because expectations are set clearly upfront
• A stronger employer reputation, because people who feel well treated talk about it
• A business that runs more smoothly, because every new person joins with the same strong foundations

It is also worth being honest about what poor onboarding reveals. If you do not have documented policies, properly drafted contracts, or a clear structure for how people are managed, that is not just a risk during onboarding. It is a risk every day. The good news is that it is entirely fixable, and getting it right does not have to be complicated.

Related Reading

If you found this post useful, you might also want to read:

• Capability vs Disciplinary: Understanding the Differences
• Phased Return to Work: What You Need to Know

Need Help Getting Your HR Foundations Right?

If you are bringing new people into your business but your employment contracts, handbooks, or policies are not in good shape, now is the time to sort that out. Not after something goes wrong.

At J Mann Associates, we work with small and medium business owners across Wiltshire and beyond to put in place the legal protections and people management structures that make running a team genuinely straightforward. Whether you need bespoke employment contracts, a fully tailored employee handbook, or solid workplace policies and procedures, you get expert support that reflects how your business actually works.

And if onboarding has not gone to plan and you are now managing a conduct or capability issue, our disciplinary and performance management team can guide you through the process safely and legally.

Get in touch to talk through what you need.

Contact us here or Book a free HR consultation call