| Game |
| Result | Moves |
Year | Event/Locale | Opening |
| 1. A Miller vs R Costigan |
| 1-0 | 37 | 1976 | 2nd Hartford Open | A44 Old Benoni Defense |
| 2. M Ginsburg vs R Costigan |
 | 1-0 | 18 | 1977 | USATE | A35 English, Symmetrical |
| 3. Seirawan vs R Costigan |
| 1-0 | 29 | 1977 | 78th US Open | A28 English |
| 4. R Costigan vs K Spraggett |
| 1-0 | 28 | 1977 | 78th US Open | B51 Sicilian, Canal-Sokolsky (Rossolimo) Attack |
| 5. R Costigan vs L Day |
| 0-1 | 46 | 1980 | 8th World Open | B06 Robatsch |
| 6. J Fedorowicz vs R Costigan |
| ½-½ | 47 | 1986 | 14th World Open | A53 Old Indian |
| 7. I L Thomas vs R Costigan |
| 1-0 | 59 | 1987 | Toronto Winter Fest | B32 Sicilian |
| 8. M Wilder vs R Costigan |
| 1-0 | 50 | 1987 | Toronto Winter Fest | A53 Old Indian |
| 9. L Witt vs R Costigan |
| ½-½ | 23 | 1987 | Toronto Winter Fest | A07 King's Indian Attack |
| 10. R Costigan vs F Behrhorst |
| 0-1 | 39 | 1987 | Toronto Winter Fest | B02 Alekhine's Defense |
| 11. R Pelts vs R Costigan |
| ½-½ | 19 | 1987 | Toronto Winter Fest | A15 English |
| 12. R Costigan vs K Spraggett |
| 0-1 | 60 | 1987 | Toronto Winter Fest | A46 Queen's Pawn Game |
| 13. R Stone vs R Costigan |
| ½-½ | 61 | 1987 | Toronto Winter Fest | D17 Queen's Gambit Declined Slav |
| 14. R Costigan vs L Day |
| 1-0 | 49 | 1987 | Toronto Winter Fest | A46 Queen's Pawn Game |
| 15. J Pajak vs R Costigan |
| 1-0 | 38 | 1987 | Toronto Winter Fest | B33 Sicilian |
| 16. R Costigan vs B Nickoloff |
| ½-½ | 46 | 1987 | Toronto Winter Fest | D02 Queen's Pawn Game |
| 17. R Costigan vs I Findlay |
| 1-0 | 46 | 1987 | Toronto Winter Fest | D02 Queen's Pawn Game |
| 18. R Costigan vs Reshevsky |
| 0-1 | 36 | 1987 | 15th World Open | A46 Queen's Pawn Game |
| 19. A Soltis vs R Costigan |
| 1-0 | 49 | 1988 | Bermuda International Open | C77 Ruy Lopez |
| 20. R Costigan vs L Baquero |
| 0-1 | 53 | 1989 | Philadelphia | D02 Queen's Pawn Game |
| 21. G Garcia vs R Costigan |
| 1-0 | 32 | 1989 | Philadelphia | C97 Ruy Lopez, Closed, Chigorin |
| 22. R Szmetan vs R Costigan |
| 1-0 | 32 | 1989 | Philadelphia | A53 Old Indian |
| 23. R Costigan vs B Rind |
| 0-1 | 33 | 1989 | Philadelphia | B24 Sicilian, Closed |
| 24. L Klein vs R Costigan |
| ½-½ | 60 | 1989 | Philadelphia | A53 Old Indian |
| 25. M Shahade vs R Costigan |
| 1-0 | 34 | 1989 | Philadelphia | A43 Old Benoni |
Kibitzing
