If you’ve ever sat down to enjoy a few spins on your favorite online slot and activated a bonus feature, you may have noticed something curious—your wins don’t feel as frequent or as generous as you’d expect. You’re not imagining things. In some cases, slots reduce their RTP (Return to Player) during bonus features, particularly when playing through a promotional bonus. This topic has gained attention, especially among users of casino sites not on GamStop, where bonus structures and game providers often operate outside the rigid framework of UKGC regulations.

As someone who has spent years reviewing online casinos and exploring the mechanics behind slot games, I’ve found this topic both fascinating and necessary to unpack for everyday players. Understanding how and why RTP can shift during bonus play can help you manage expectations, protect your bankroll, and even choose better games or platforms for long-term success.

What Is RTP and Why Does It Matter?

RTP, or Return to Player, is the theoretical percentage of wagered money that a slot machine will return to players over time. For example, if a slot has an RTP of 96%, it means that over the long haul, players will receive back £96 for every £100 wagered.

Now, this doesn’t mean that every player will get that precise return—it’s an average over many spins, across all users. One person might win big, another might walk away with nothing. But RTP gives us a foundational expectation of fairness and volatility.

When bonuses come into play—especially deposit match bonuses or free spins—many casinos, including casino sites not on GamStop, apply alternate game settings that can affect the RTP.

How Bonuses Can Affect RTP in Slots

Most casual players assume that once they activate a bonus, they’re playing the same game with the same odds. But behind the scenes, software developers and casinos can tweak RTP settings based on bonus activation or the terms of a promotion.

Here are a few ways this can happen:

1. Bonus Terms Include Alternative RTP Versions

Some slots come in multiple RTP configurations—e.g., 96%, 94%, or even 88%. When a casino offers a bonus, particularly on non-UK sites, they may configure the bonus play version of the slot to a lower RTP variant. It’s not a glitch or a scam per se; rather, it’s a practice that casinos are legally allowed to do—especially on casino sites not on GamStop, where they’re not subject to strict UKGC oversight.

The rationale is simple: a lower RTP version of a game helps the casino offset the cost of the bonus funds. While players receive something “free,” the house regains that advantage subtly over the course of gameplay.

2. Game Providers Allow RTP Changes Based on Play Mode

Another subtle trick lies within the game providers themselves. Some developers create games that allow casinos to toggle different RTP settings based on whether the player is using real money or bonus funds. When you switch from cash play to bonus play, the version of the slot you’re using may change, even if the game appears visually identical.

On reputable UK sites, this tactic would typically require transparency or even be prohibited. But on casino sites not on GamStop, transparency isn’t always enforced, and RTP switches during bonus play can go unnoticed unless players actively check game information during each phase of gameplay.

3. Wagering Requirements & RTP Adjustment

Many bonuses come with wagering requirements—you need to wager a certain amount before you can withdraw winnings. During this period, casinos might reduce slot RTPs to make it less likely that you will hit big wins that allow you to complete those requirements quickly.

While this might feel unfair, it’s one of the ways casinos balance their risk when giving out bonuses. This tactic is more common on non-GamStop casinos, where bonus abuse is more prevalent due to relaxed registration and identity verification rules.

Are Casinos Doing Anything Wrong?

From a legal perspective, many of these actions fall into a gray area. Slot RTP variation is not illegal, and it’s often included in the game’s technical details or terms and conditions—if you know where to look.

However, the ethical concern lies in transparency. If a casino lowers RTP without clear notification to the player, that’s misleading. Players make decisions based on perceived odds, and anything that subtly changes those odds without clear disclosure erodes trust.

In the UK and other regulated markets, gaming commissions are starting to clamp down on these practices. But casino sites not on GamStop operate outside these boundaries, which can lead to greater risk for players who aren’t vigilant.

Why This Happens More on Non-GamStop Casinos

If you’re unfamiliar with the term, casino sites not on GamStop are online casinos that do not participate in the UK’s self-exclusion scheme. These sites are often licensed in jurisdictions like Curacao or Malta and may cater to UK players who have chosen to self-exclude from UKGC-licensed platforms.

These casinos tend to offer:

• More generous bonuses

• Fewer restrictions on gameplay

• Higher withdrawal limits

But with these perks come fewer safeguards. These sites are not legally bound to follow UK advertising standards, fairness protocols, or responsible gaming practices. That includes the ability to modify RTP settings more freely—especially during promotional periods.

From a player’s standpoint, this can be a double-edged sword. You might enjoy more gameplay freedom, but the cost can come in the form of reduced RTP, obscure bonus terms, and limited dispute resolution avenues.

How to Protect Yourself as a Player

Understanding RTP manipulation and bonus mechanics is your first defense. Here are a few real-world tips that I’ve followed and recommend:

Always read the bonus terms thoroughly. Some casinos disclose that bonus play occurs on alternative RTP versions of games. Look for terms like “reduced RTP,” “bonus RTP configuration,” or “game version during bonus.”

Compare RTP before and during bonus play. Some games let you access an info menu (the little ‘i’ button). Use it to check the RTP percentage. Do this during both regular and bonus gameplay. If you notice a drop from 96% to 91%, you’ll know what’s happening.

Stick with trusted providers. Not all casino sites not on GamStop are shady, but some have better reputations than others. Look for third-party reviews, forums, and player feedback.

Avoid chasing high bonuses without understanding the cost. A 200% match bonus looks tempting—but if it’s tied to high wagering and a low RTP environment, you may be better off playing with your own cash.

Are All Bonuses Bad?

Definitely not. Bonuses are part of the fun and can provide real value—when used wisely. But in the modern iGaming landscape, especially outside regulated environments, players need to be more informed than ever.

Some non-GamStop casinos offer transparent bonuses with fair wagering and clearly stated RTPs. These platforms know that building long-term player trust is more valuable than squeezing short-term profits through hidden mechanics.

So while RTP reduction during bonuses is real, it’s not universal. The key is being able to recognize when it’s happening, and making your gameplay decisions accordingly.

Final Thoughts

The world of online slots and casino bonuses is more complex than it appears on the surface. While RTP is meant to serve as a benchmark for fairness, it can be adjusted by casinos, especially during bonus play. This is particularly true on casino sites not on GamStop, where regulation is lighter and bonus strategies are more aggressive.

As a player, your job isn’t just to chase wins but to play smart. That means learning how game settings shift, how casinos structure bonuses, and how to spot signs of reduced RTP. The more you understand about what’s going on behind the scenes, the better your chances of making the most of your online gaming experience—without any unpleasant surprises.

Stay sharp, and always check the small print. The more informed you are, the better you’ll navigate the ever-evolving landscape of online casinos.