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  <xsd:element id="omex_ExplorationLicense" name="ExplorationLicense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="omex_ExplorationLicenseImpairments" name="ExplorationLicenseImpairments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="omex_GainOnDebtForgiveness" name="GainOnDebtForgiveness" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="omex_InterestExpensesOnLoansPayable" name="InterestExpensesOnLoansPayable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="omex_InterestFromFeeAmortization" name="InterestFromFeeAmortization" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="omex_InvestmentAgreementPeriod" name="InvestmentAgreementPeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="omex_InvestmentsOptionsExercisePrice" name="InvestmentsOptionsExercisePrice" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="omex_MaximumAmountOfFinancingAvailableFromFutureIssuanceOfConvertiblePreferredStock" name="MaximumAmountOfFinancingAvailableFromFutureIssuanceOfConvertiblePreferredStock" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="omex_NetIncomeLossAvailableToCommonStockholdersBasicAndDiluted" name="NetIncomeLossAvailableToCommonStockholdersBasicAndDiluted" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="omex_NumberOfOutsideDirectorsGrantedQuarterlyFees" name="NumberOfOutsideDirectorsGrantedQuarterlyFees" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="omex_OfferingFeesWithheldToCoverOfferingCosts" name="OfferingFeesWithheldToCoverOfferingCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="omex_OperationsAndResearchExpense" name="OperationsAndResearchExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="omex_PaymentOfOperatingLeaseLiability" name="PaymentOfOperatingLeaseLiability" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="omex_PercentageOfFaceValueOfNote" name="PercentageOfFaceValueOfNote" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="omex_PercentageOfNumberOfSharesIssuedAfterExerciseNotice" name="PercentageOfNumberOfSharesIssuedAfterExerciseNotice" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="omex_PercentageOfOutstandingVotingSecurities" name="PercentageOfOutstandingVotingSecurities" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="omex_PercentageOfPaymentOfUnpaidPrincipalAmount" name="PercentageOfPaymentOfUnpaidPrincipalAmount" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="omex_PercentageOfPaymentOfUnpaidPrincipalAmountAfterExerciseNotice" name="PercentageOfPaymentOfUnpaidPrincipalAmountAfterExerciseNotice" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="omex_PercentageOfSharesOutstandingPostConversion" name="PercentageOfSharesOutstandingPostConversion" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="omex_PrepaymentNoticePriorToRepaymentPeriod" name="PrepaymentNoticePriorToRepaymentPeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="omex_ProceedsFromSaleOfEquityOfSubsidiary" name="ProceedsFromSaleOfEquityOfSubsidiary" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="omex_PropertyPlantAndEquipmentSubjectToOperatingLeases" name="PropertyPlantAndEquipmentSubjectToOperatingLeases" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="omex_PurchasePriceOfWarrant" name="PurchasePriceOfWarrant" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="omex_ReimbursementOfPurchaseOfTheEquipment" name="ReimbursementOfPurchaseOfTheEquipment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="omex_RepurchaseOfStockbasedAwardsWithheldForPaymentOfWithholdingTaxRequirements" name="RepurchaseOfStockbasedAwardsWithheldForPaymentOfWithholdingTaxRequirements" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="omex_SharesUsedInComputationForEarningPerShareBasic" name="SharesUsedInComputationForEarningPerShareBasic" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="omex_ShortTermInvestmentsMaturityPeriod" name="ShortTermInvestmentsMaturityPeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="omex_WorkingCapitalDeficit" name="WorkingCapitalDeficit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="omex_AgreementTypeDomain" name="AgreementTypeDomain" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_FunderDomain" name="FunderDomain" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_IncomeTaxesLineItems" name="IncomeTaxesLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_BackOfficeTechnicalAndSupportServicesMember" name="BackOfficeTechnicalAndSupportServicesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_CorporateOfficeSpaceMember" name="CorporateOfficeSpaceMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_DeepSeaMineralCompanyMember" name="DeepSeaMineralCompanyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_ElevenEmergencyInjuryDisasterLoanMember" name="ElevenEmergencyInjuryDisasterLoanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_EpsilonAcquisitionsLLCMember" name="EpsilonAcquisitionsLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_GregStemmMember" name="GregStemmMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_IncentiveStockOptionsMember" name="IncentiveStockOptionsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_InMoneyPotentialCommonSharesMember" name="InMoneyPotentialCommonSharesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_LitigationFinancingMember" name="LitigationFinancingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_ManacoMember" name="ManacoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_MarineOperationsMember" name="MarineOperationsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_MarineServicesMember" name="MarineServicesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_MinosaMember" name="MinosaMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_MinosaOneMember" name="MinosaOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_MinosaTwoMember" name="MinosaTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_MrGordonsEmploymentAgreementMember" name="MrGordonsEmploymentAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_NonCashLitigationFinancingMember" name="NonCashLitigationFinancingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_NoteOneToNoteThirteenMember" name="NoteOneToNoteThirteenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_NotePurchaseAgreementMember" name="NotePurchaseAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_OmexDeepSeaMineralCompanyMember" name="OmexDeepSeaMineralCompanyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_OperatingAndOtherMember" name="OperatingAndOtherMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_OperatingLossCarryforwardsExpiringTwoThousandAndTwentyEightThroughTwoThousandAndThirtySevenMember" name="OperatingLossCarryforwardsExpiringTwoThousandAndTwentyEightThroughTwoThousandAndThirtySevenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_OperatingLossCarryforwardsExpiringTwoThousandAndTwentyFiveThroughTwoThousandAndTwentySevenMember" name="OperatingLossCarryforwardsExpiringTwoThousandAndTwentyFiveThroughTwoThousandAndTwentySevenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_OtherAccountsReceivableMember" name="OtherAccountsReceivableMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_OutOfMoneyPotentialCommonSharesMember" name="OutOfMoneyPotentialCommonSharesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_PenelopeMiningLlcMember" name="PenelopeMiningLlcMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_PoplarFallsLlcMember" name="PoplarFallsLlcMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_RelatedPartyMember" name="RelatedPartyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_StockOptionsWithExercisePriceOfFivePointSevenSixMember" name="StockOptionsWithExercisePriceOfFivePointSevenSixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_StockOptionsWithExercisePriceOfFourPointSevenFiveMember" name="StockOptionsWithExercisePriceOfFourPointSevenFiveMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_StockOptionsWithExercisePriceOfFourPointSixSevenMember" name="StockOptionsWithExercisePriceOfFourPointSixSevenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_StockOptionsWithExercisePriceOfThreePointFiveNineMember" name="StockOptionsWithExercisePriceOfThreePointFiveNineMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_StockOptionsWithExercisePriceOfThreePointFourTwoMember" name="StockOptionsWithExercisePriceOfThreePointFourTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_StockOptionsWithExercisePriceOfThreePointNineNineMember" name="StockOptionsWithExercisePriceOfThreePointNineNineMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_StockOptionsWithExercisePriceOfThreePointThreeFiveMember" name="StockOptionsWithExercisePriceOfThreePointThreeFiveMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_StockOptionsWithExercisePriceOfTwelvePointEightFourMember" name="StockOptionsWithExercisePriceOfTwelvePointEightFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_StockOptionsWithExercisePriceOfTwelvePointFourEightMember" name="StockOptionsWithExercisePriceOfTwelvePointFourEightMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_StockOptionsWithExercisePriceOfTwentySixPointFourZeroMember" name="StockOptionsWithExercisePriceOfTwentySixPointFourZeroMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_ThirtySevenNorthMember" name="ThirtySevenNorthMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_TwoThousandNineteenStockIncentivePlanMember" name="TwoThousandNineteenStockIncentivePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_VendorNotePayableMember" name="VendorNotePayableMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_WarrantsWithExercisePriceOfSevenPointOneSixMember" name="WarrantsWithExercisePriceOfSevenPointOneSixMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_IncomeTaxesTable" name="IncomeTaxesTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="omex_ExplorationLicensesPolicyTextBlock" name="ExplorationLicensesPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="omex_LoansPayableTextBlock" name="LoansPayableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
</xsd:schema>
