MechWarrior Online – Ultimate Flea Guide (Become an Elite FleaWarrior)

For pilots crazy enough to pilot Fleas as their primary mech of choice.

Definitive Guide to Flea


The Flea is the epitome of high risk, high reward gameplay! 1000+ damage awaits those who choose to master the craft of Fleaing.

With all my time in the Flea, I’ve learned a lot, and am still continuing to realize new things! Some of this guide is general knowledge and applies to other mechs as well. Either way, I hope this helps someone become a better Flea pilot! Some of it will be brief notes, tidbits of good-to-know info. And if you don’t Flea, try to protect your Flea battle buddies on the field! They can help immensely if they know what they’re doing.



If you’re in a Flea 20 with ECM and ECM skill nodes, remember these ranges:

  • > 255m (256m and beyond) gives you stealth (enemies cannot target you and reveal you to their entire team).
  • < 120m (119m and within) gives you jamming (enemies cannot lock on with missiles and cannot share targeting data with the rest of their team). Keep in mind enemies will know you’re in the vicinity from seeing “low signal” on their mini map!
  • It’s also good to keep these in mind if you’re in a non-ECM Flea and you encounter an ECM mech!

Use ECM counter mode (disrupt is default, press J to toggle) when you need your team to target an ECM mech you have targeted (turns off disrupt so you will no longer have stealth or jamming by disrupting enemy targeting).

Weapon Ranges

These aren’t weapons used by Fleas, but as a Flea pilot, you must know about enemy mechs you may come across. If you see a mech with primarily these weapons, take advantage of it and charge in for the kill!

  • Inner Sphere LRM only does damage 180m and beyond..
  • Clan LRM has exponential damage fall within 180m.
  • ATM only does damage 120m and beyond.
  • PPC has exponential damage fall within 90m.
  • Heavy PPC does no damage within 90m.

Dangerous Weapons

If you see anything that does high pinpoint damage or certain missiles, like IS AC20s, SRMs, Streaks, PPC, Gauss, be extra cautious or run away! Rotaries, UACs, and some clan autocannons, are a bit easier to deal with (more Flea friendly lol). If you see a RAC mech, just keep peeking, as they need time to spin up!

Small Lasers And Their Ranges

As a Flea pilot, you’ll be using a lot of small lasers. So it’s important to get familiar with their ranges (use these as approximations, as some range skill nodes may change these).

  • Small pulse laser: 145m optimal – 291 max (218m to do 50% damage).
  • Small laser: 172m optimal – 345m max (258m to do 50% damage).
  • ER small laser: 216m optimal – 432m max (324m to do 50% damage).

So practical max effective range is around 200m and 300m with ER small lasers.

Situational Awareness

This is really important in a Flea with so little armor, to prevent turning a wrong corner, getting hit from an unseen enemy, or to find opportunities to strike. Over time, you will begin to feel the “heat” of the battlefield with your intuition and instinct. When no enemies are spotted and nobody is firing or getting hit, there is no “heat”. On the other hand, when activity is high (teammates calling for help, constant sound of mechs getting hit left and right, and just chaos in general) the Flea shines, as distracted enemies are sure kills!

When you attack, only attack if you can commit, because running away usually results in a Viper or Piranha chasing to leg you, getting shot in the back, or taking unnecessary damage. If there are too many mechs, wait for team support. To assess, assume their whole team could come to your position of attack, because remember once an enemy mech targets you, their whole team can see you, so do you have enough teammates around backing you up? If not, hold position and do not attack. If there are two away from the group, only attack if you have a plan and prioritize your targets (for example, one is a LRM boat and one is a Locust, so prioritize the Locust).

Keep your eye on the mini-map and try to feel the higher level perspective of what’s going on all around you. Flea pilots rely on the team more than most other mechs! Also, keep a habit of zooming in and out frequently, because forgetting to zoom out could mean not seeing a mech that’s about to kill you, and it’s also really hard to fight close range when zoomed in. Also remember to treat armor as a consumable just like ammo! Conserve it as much as you can, but know when to use it (when it’s max heat)!


  • The Flea’s speed makes it a great flanker and backstabber. The only time you’d want to fire at an enemy mech facing you, is when they’re under fire from friendly mechs, or busy shooting friendly mechs.
  • In general, always press R to target what you’re about to attack! And always pick a specific component to focus on! Even in tier 1, I see some players who don’t do this. Also take a quick glance at the loadout if you can. When using lasers, hold the beam on the component as best as you can until it finishes burning (otherwise the damage is spread). When using SRMs/MRMs, lead the shot when the target is moving. Use arm lock if you’re mainly long range and have weapon groups mixed with arms and torso for extra concentration of damage, otherwise keep it off for better aiming flexibility, and quicker torso turning in close range.
  • Peeking is very effective and a relatively safe way to attack when compared to charging in to brawl, and you can quickly rack up damage done. When peeking, make sure to expose the min amount of yourself for the shortest time possible (so make sure to MASC out, alpha strike, MASC in!), and peek from a different spot, or switch up your peeking rhythm when the enemy notices you. There are two types of peeking: horizontal peeks around the corner, and vertical peeks with elevation differences (an enemy coming up over an incline, or an enemy exposing its top below you). Reverse peeking is when you back out of cover, to be able to go forward into cover quicker.
  • Hit and run is useful when you see an instant kill or a weak component. It’s also useful when you need to keep moving and attacking at the same time. In a Flea, be sure to use MASC to allow you to fire as frequently as possible (run 90 degrees to the enemies FOV and fire with a turned torso, MASC U-turn as you turn torso in the direction of the mech to fire again, and repeat to keep firing and moving within the same area).
  • Circling is the most common but there are some tips to keep in mind! Most players fire constantly as they circle (which is fine with machine guns), but as a Flea pilot, you need to be as effective and deadly as possible, so time your fire at components you target (e.g. rear CT), and save your MASC for a short burst when you’re within the enemy’s FOV, then let it recharge while giving you more time for a shot to the rear CT. You want to keep the radius of the circle as tight as you can, because the bigger the radius, the slower you appear to go to the enemy, and the longer it takes for you to make one full circle.
  • Rear CT/ST is probably the most efficient way for kills (besides headshots) in a Flea with limited firepower and extreme agility. This is best performed on lone mechs that are slow, or distracted mechs/mechs under fire! Here are some tips:
    • You want to stay completely out of sight of the enemy! So keep using bursts of MASC to maneuver and stay behind the mech. Imagine instant death if you end up in the enemy’s sights. It’s important to remember that the closer you are to your target, the faster you can maneuver around it, so close the distance quickly, and keep it tight!
    • When shooting the CT, aim for dead center, as you may be damaging the side torso instead (unless the mech has one torso left or has a dangerous torso you’d like to destroy, then go for the torso!) and if you can’t get a good shot on it, aim for the center of the butt, which also counts as rear CT damage!
    • Even at an angle, or when the enemy is attempting to back up towards a wall (coward lol), angled shots towards the rear CT/butt also work. When you see a mech trying to back against a wall, go behind them so they end up backing into you instead of the wall. If you’re shooting at an angle, and the mech is going backwards, be sure you have your legs positioned to be able to follow them back, otherwise you’ll lost sight of their rear and will soon be facing the mech head on.
    • This attack is not only reserved for slow mechs! Linebackers, Shadow Cats, and lights are also juicy targets. When a light is running away, they are easy kills in Fleas that can keep up. They often don’t expect another mech to keep up, so they keep running, giving you plenty of shots.
    • Don’t stop moving! It’s tempting to stay still to keep firing, but don’t do it. Go back and forth, forward forward back back, etc.


  • The best armor is not to get hit! Play as if your CT is already open red, because it’s just one mistake away from it truly being so.
  • Situational awareness! As mentioned earlier, situational awareness is key to survival. One important note to add is to always keep in mind that if an enemy spots you, their whole team also sees you, since targeting data is distributed among the team! But this can also be used to your advantage if your goal is to distract the enemy team, or lure them into friendly firing lines.
  • Keep moving forward and don’t stop moving! Fleas rely on evasion more than armor for defense, so one of the worst things you could do is to stay still when the battlefield is hot, even for a brief second, because that’s all it takes for you to be instantly killed. One of the most common mistakes I see, are pilots going backwards. Going straight back is the worst, because you stay within the enemy’s FOV, and it does absolutely nothing good for you. You’d rather back up 90 degrees, or sideways, to the enemy’s FOV, but why go backwards when you can go forward? Lights are fast, and speed is your greatest advantage, but when you reverse, you go slow, not to mention the brief moment where you’re basically standing still every time you back up then decide to go forward again! The only time you should back up is to maintain a rear CT shot, or MASC back and forth forward and back when focusing on firing at a component, or when backing up to cover.
  • MASC
    • Some pilots haven’t realized that the greatest advantage to MASC isn’t the speed, but the 50% turn rate boost for agility, and the boost in acceleration/deceleration! So make it a habit using MASC to turn and to quickly change direction! This comes in extra handy when trying to stay behind a mech for a rear CT kill, or when trying to dodge and evade shots.
    • MASC is limited, so use them in bursts! Skilled Flea pilots are able to consistently use MASC, even near the redline, but using it in short bursts and relying on the sound as an indication of how much more they can apply. Also, remember to let it cool down whenever you’re in the air!
    • MASC messes up your aim, so practice firing after aim has settled. It’s easy to have this happen when using MASC to peek and hide quickly, so practice!
    • Use MASC when peeking! As mentioned before, you want to peek and go back to cover as fast as you can. Do a quick burst out of cover (practice not over-exposing yourself!) as you alpha strike followed by a quick burst back to cover.
  • Evasion
    • Best done 90 degrees to enemy mech’s FOV, with erratic unpredictable patterns, when closing the distance or retreating. Combine with moving the torso (torso twisting) to spread laser damage or to protect critical components. Use MASC every time you turn and turn often!
    • Keep in mind that the acceleration burst from a MASC burst is what will most likely dodge a shot. Combine MASC bursts with a change in direction for greater effect.
  • Legs
    • If you’re legged or a leg is weak, use cover to your advantage (peeking up over hills to force them to shoot upper part of your mech).
    • If left leg is weak, circle enemies clockwise, and vice versa.
  • LRMs
    • Always be aware of what direction LRMs are coming from. You can check for a trail of smoke left behind from the missiles if you missed where it was coming from at first. If there’s no cover around the best thing to do is to run full speed perpendicular from where the missiles are coming from.


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