It's time to begin another pivotal week on the diamond, and new users can claim thousands of dollars in bonus bets with the best MLB betting promos for Monday, August 31, 2026.
Tonight's MLB odds feature a 12-game slate, starting with the Marlins vs. Nationals at 6:45 p.m. ET on FS1. Other big games, like Brewers vs. Cubs and Phillies vs. Diamondbacks, have postseason implications that make these games a little more worthwhile.
Check out the top MLB betting promos below for the chance to claim thousands in bonus funds. There are plenty of unique offers to take advantage of, with some only requiring a deposit or first-time wager, while some give you a backstop to claim bonus bets if your first wager loses. Let's see what these deals have to offer:
| MLB Sportsbook | MLB Betting Promo | Sign-Up Link |
| Fanatics Sportsbook | $1,000 Bet Match | ACTION26 |
| BetMGM | $1,500 First Bet Offer | TOPACTION |
| bet365 | Bet $10, Get $365 Bonus + 50 Casino Spins | Click Here |
| DraftKings Sportsbook | $150 Bet-and-Get Promo | Click Here |
| FanDuel Sportsbook | Get $350 in Bonus Bets Over 7 Days | Click Here |
| theScore Bet | $1,000 First Bet Reset | ACTNEWS |
| betPARX | $50 Bet Insurance | TANBONUS |
| Hard Rock Bet | $150 Bet-and-Get Promo | Click Here |
MLB Schedule for Monday, August 31
- San Francisco Giants at Atlanta Braves, 6:05 p.m. ET
- New York Mets at Tampa Bay Rays, 6:40 p.m. ET
- San Diego Padres at Cincinnati Reds, 6:40 p.m. ET
- Miami Marlins at Washington Nationals, 6:45 p.m. ET (FS1)
- Seattle Mariners at Boston Red Sox, 6:45 p.m. ET
- Detroit Tigers at Minnesota Twins, 7:40 p.m. ET
- Milwaukee Brewers at Chicago Cubs, 7:40 p.m. ET
- Athletics at Texas Rangers, 8:05 p.m. ET
- Chicago White Sox at Houston Astros, 8:10 p.m. ET
- Baltimore Orioles at Colorado Rockies, 8:40 p.m. ET
- New York Yankees at Los Angeles Angels, 9:38 p.m. ET
- Philadelphia Phillies at Arizona Diamondbacks, 9:40 p.m. ET
Best MLB Betting Promos for Monday, August 31
Action Network has compiled a list of the top eight MLB betting promos for Monday, August 31, 2026. New users can get started by signing up for one or all of these sportsbook promos, as long as they aren't already signed up. Without further ado, let's break it all down before first pitch tonight:
1. Fanatics Sportsbook Promo Code
Sign up with Fanatics Sportsbook promo code ACTION26 and you'll unlock a $1,000 Bet Match spread across 10 days. The structure is simple: place a wager on an eligible game each day, and if it loses, Fanatics refunds you in bonus bets up to $100. Bet $100 and lose? You get $100 back in bonus bets. Bet $50 and lose? You get $50. The refund matches your stake, so smaller bets mean smaller returns.
Loss-forgiveness offers like this one are among my favorite MLB betting promos because they give you room to swing at longer odds than you normally would; a losing ticket still leaves you with something to work with the next day.
Because the promotion runs for 10 days during baseball season, you'll likely need to branch out beyond MLB — college football odds are a natural place to look if you want to keep collecting daily. One last note: Fanatics runs different welcome offers by state, so check what's available in your location, as the alternate promo may be your only option.
| Fanatics Sportsbook Promo | Fanatics Sportsbook Sign-Up Bonus | Fanatics Sportsbook Legal States |
|---|---|---|
| Fanatics Sportsbook Promo Code ACTION26 | $1,000 Bet Match | AZ, CO, CT, DC, IA, IL, IN, KS, KY, LA, MA, MD, MI, MO, NC, NJ, NY, OH, PA, TN, VA, VT, WV, WY |
| Fanatics Sportsbook Promo Code (Click Here) | Bet $20, Get $350 in Bonus Bets | AZ, CO, CT, DC, IA, IN, KS, KY, LA, MA, MD, MI, MO, NC, NJ, OH, PA, TN, VA, VT, WV, WY |
| Fanatics Sportsbook Promo Code (Click Here) | Get 10x100% Profit Boost Tokens Instantly | IL, NY |
2. BetMGM Bonus Code
The BetMGM bonus code TOPACTION carries the highest dollar value for any MLB betting promos in this article. It's a one-shot deal: if your first wager loses, BetMGM returns up to $1,500 in bonus bets. As with Fanatics, BetMGM runs several different welcome offers, so confirm which one applies in your state before signing up.
It might sound aggressive, but it's a solid spot to take a swing at a big underdog. Baseball produces more upsets than just about any sport — plus-money road dogs cash regularly, and a $1,500 wager on a live underdog would pay off in a serious way. And if the favorite holds? You still walk away with $1,500 in bonus bets to work with. That's a reasonable trade-off either way.
| BetMGM Bonus Code | BetMGM Promo | BetMGM Legal States |
|---|---|---|
| BetMGM Bonus Code TOPACTION | $1,500 First Bet Offer | AZ, CO, DC, IA, IL, IN, LA, KS, KY, MA, MD, NC, OH, TN, VA, WY |
| BetMGM Bonus Code TANGET2 | $1,000 No Sweat Tokens | AZ, CO, DC, IA, IL, IN, LA, KS, KY, MD, MO, NC, OH, TN, VA, WY |
| BetMGM Bonus Code ACTIONGET | Bet $10, Get $150 Bonus Bets if You Win | MI, NJ, PA, WV |
3. bet365 Bonus Code
The bet365 bonus code terms were recently upgraded, and it now ranks among the strongest MLB betting promos for new users. All it takes is a $10 first-time wager. Win or lose, you'll receive $365 in bonus bets plus 50 casino spins. That's more than double what bet365 was handing out before, and the offer expires Sept. 22, so don't sit on this meatball right down the middle of the plate.
Here's the funny part: bet365 is one of the few books I haven't signed up with yet. The plan is to jump in and put that $365 to work on home run parlays down the stretch of the pennant race. Long shots, sure, but that's exactly what bonus bets are for. I'd like to think this kind of forward planning would make me a decent bench coach.
| bet365 Bonus Code | bet365 Welcome Promo | bet365 Legal States |
|---|---|---|
| bet365 Bonus Code (Click Here) | Bet $10, Get $365 in Bonus Bets, Win or Lose | AZ, CO, IA, IN, KS, KY, LA, MD, MI, MO, NC, NJ, OH, PA, VA |
| bet365 Bonus Code (Click Here) | $1,000 First Bet Safety Net | AZ, CO, IA, IL, IN, KS, KY, LA, MD, MO, NC, OH, TN, VA |
| bet365 Bonus Code (Click Here) | Bet $10, Get $150 in Bonus Bets, Win or Lose, 50 Casino Spins | IL, TN |
4. DraftKings Promo Code
The DraftKings promo code recently refreshed, and the new terms are an improvement. Place a first-time wager of $5 or more, and you'll collect $200 in bonus bets. The payout arrives in four $50 installments: the first hits once your qualifying bet is placed, then another $50 lands every seven days after that.
This is about as low-friction as MLB betting promos get — five bucks on any game gets you started, and the result of that first bet doesn't matter. The catch is that plenty of bettors already have DraftKings accounts and won't qualify. If you're one of the holdouts, there's no better time to give them a look than the back half of the season.
| DraftKings Promo Code | DraftKings Welcome Offer | DraftKings Legal States |
|---|---|---|
| DraftKings Promo Code (Click Here) | Spend $5, Get $200 in Bonus Bets | AR, AZ, CO, DC, IA, IL, IN, KS, KY, LA, MA, MD, MI, MO, NC, NJ, NY, OH, PA, TN, VA, VT, WV, WY |
5. FanDuel Promo Code
Sportsbooks across the board are reworking their welcome offers, and the FanDuel promo code follows suit. FanDuel's updated deal asks new users to place a $5+ bet once a day for seven consecutive days. Each time one of those wagers settles, $50 in bonus bets lands in your account. Stack all seven, and you're looking at a maximum of $350, which puts it near the top of the MLB betting promos on this list.
This structure works well because you're getting a fresh reload every day for a full week. If I were signing up, I'd knock out the seven-day requirement while the regular season is still winding down, then head into the playoff race with $350 in bonus bets ready to go. Nothing wrong with walking into October with ducks on the pond.
| FanDuel Promo Code | FanDuel Sign-Up Bonus | FanDuel Legal States |
|---|---|---|
| FanDuel Promo Code (Click Here) | Get $350 in Bonus Bets When You Bet $5 for 7 Days | AZ, AR, CO, CT, DC, IL, IA, IN, KS, KY, LA, MA, MD, MI, MO, NC, NJ, NY, OH, PA, TN, VA, VT, WV, WY |
6. theScore Bet Promo Code ACTNEWS
In most states, theScore Bet promo code ACTNEWS unlocks a $1,000 First Bet Reset for new users. Put your opening wager on any MLB game, and if it comes up short, theScore Bet reimburses you with up to $1,000 in bonus bets.
A separate version of the offer is running in Michigan, New Jersey, Pennsylvania, and West Virginia. In those states, the structure flips: place a first-time bet of $10 or more, and you'll pick up $100 in bonus bets if it wins. Worth checking which version applies to you before locking anything in.
| theScore Bet Promo Code | theScore Bet Welcome Offer | theScore Bet Legal States |
|---|---|---|
| theScore Bet Promo Code ACTNEWS | $1,000 First Bet Reset | AZ, CO, IA, IL, IN, KS, KY, LA, MA, MD, MO, NC, OH, TN, VA |
| theScore Bet Promo Code ACTNEWS | Bet $10, Get $100 in Bonus Bets If You Win | MI, NJ, PA, WV |
7. betPARX Promo Code TANBONUS
It won't top the list of most lucrative MLB betting promos, but the betPARX promo code TANBONUS comes with 100% bet insurance: if your first wager loses, you'll get up to $50 back in bonus bets. With a safety net like that, I'd chase the biggest number I could find. This is the perfect setup for a 10-leg parlay stitched together from the full slate of games.
One important caveat — this welcome offer is available only to bettors located in Pennsylvania.
| betPARX Promo Code | betPARX Sign-Up Offer | betPARX Legal States |
|---|---|---|
| betPARX Promo Code TANBONUS | 100% Bet Insurance, Up to $50 Bonus Bet | PA |
8. Hard Rock Bet Promo Code
With the Hard Rock Bet promo code, there's no code to punch in as you'd find with most MLB betting promos. Just click the link above and the registration process handles the rest. The offer itself is respectable without being the headliner: bet $5 and collect $100 in bonus bets if it wins. Keep in mind this one is limited to new customers in Michigan and New Jersey.
A $100 bankroll opens up a few directions worth exploring, and I'd give some thought to spreading it across four or five MLB futures. You can keep it relatively safe with a favorite like Pete Crow-Armstrong to win MVP, or roll the dice on a longer number and back a wild-card team, like the Phillies, to come out of the pennant race with a World Series title.
| Hard Rock Bet Promo Code | Hard Rock Bet Welcome Bonus | Hard Rock Bet Legal States |
|---|---|---|
| Hard Rock Bet Promo Code (Click Here) | Bet $5, Get $1o0 in Bonus Bets | MI, NJ |
MLB Prediction Markets for Monday, Aug. 31
MLB prediction markets offer another route to claiming bonuses outside the traditional sportsbook setup. If you live in a state where sports betting hasn't gone legal, this is your way into the action.
Several of the leading prediction market apps have rolled out MLB betting promos of their own. The catch is that the value doesn't stack up against what the sportsbooks above are offering. Still, free money is free money — I signed up for both offers myself and haven't regretted it.
1. Kalshi Promo Code ACTION
The Kalshi promo code ACTION comes with a refreshed welcome offer for the MLB stretch run, and it's about as simple as they come. Register for an account, place $25 worth of trades, and you'll get a $25 bonus. Consider it a solid leadoff single to get you on base in the prediction market space.
| Kalshi Promo Code | Kalshi Referral Offer | Kalshi States Available |
|---|---|---|
| Kalshi Promo Code ACTION | Trade $25, Get $25 Bonus | AK, AL, AR, CA, CO, CT, DC, DE, FL, GA, HI, IA, ID, IN, KS, KY, LA, ME, MN, MO, MS, NC, ND, NE, NH, NJ, NM, NY, OK, OR, PA, RI, SC, SD, TN, TX, UT, VA, VT, WI, WV, WY |
2. Polymarket Promo Code ACTION
The Polymarket promo code ACTION asks for a smaller upfront commitment, and the updated version of this welcome offer grants you a $50 bonus! Make a first-time deposit of $10 and a $50 trading bonus hits your account — no trading volume requirement to clear first.
| Polymarket Promo Code | Polymarket Referral Bonus | Polymarket States Available |
|---|---|---|
| Polymarket Promo Code ACTION | Deposit $10, Get $50 Trading Bonus | AK, AL, AR, CA, CO, CT, DC, DE, FL, GA, HI, IA, ID, IN, KS, KY, LA, ME, MN, MO, MS, NC, ND, NE, NH, NJ, NM, NY, OK, OR, PA, RI, SC, SD, TN, TX, UT, VA, VT, WA, WI, WV, WY |
